CVE-2026-28809 (GCVE-0-2026-28809)
Vulnerability from cvelistv5
Published
2026-03-23 10:09
Modified
2026-04-07 14:38
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-611 - Improper Restriction of XML External Entity Reference
Summary
XML External Entity (XXE) vulnerability in esaml (and its forks) allows an attacker to cause the system to read local files and incorporate their contents into processed SAML documents, and potentially perform SSRF via crafted SAML messages.
esaml parses attacker-controlled SAML messages using xmerl_scan:string/2 before signature verification without disabling XML entity expansion. On Erlang/OTP versions before 27, Xmerl allows entities by default, enabling pre-signature XXE attacks. An attacker can cause the host to read local files (e.g., Kubernetes-mounted secrets) into the SAML document. If the attacker is not a trusted SAML SP, signature verification will fail and the document is discarded, but file contents may still be exposed through logs or error messages.
This issue affects all versions of esaml, including forks by arekinath, handnot2, and dropbox. Users running on Erlang/OTP 27 or later are not affected due to Xmerl defaulting to entities disabled.
References
| URL | Tags | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||
Impacted products
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-28809",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-03-23T15:07:17.488260Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-03-23T15:52:46.187Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"cpes": [
"cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*",
"cpe:2.3:a:arekinath:esaml:*:*:*:*:*:*:*:*",
"cpe:2.3:a:handnot2:esaml:*:*:*:*:*:*:*:*"
],
"defaultStatus": "affected",
"packageName": "esaml",
"packageURL": "pkg:hex/esaml",
"product": "esaml",
"vendor": "dropbox"
},
{
"collectionURL": "https://github.com",
"cpes": [
"cpe:2.3:a:arekinath:esaml:*:*:*:*:*:*:*:*"
],
"defaultStatus": "affected",
"packageName": "arekinath/esaml",
"packageURL": "pkg:github/arekinath/esaml",
"product": "esaml",
"repo": "https://github.com/arekinath/esaml.git",
"vendor": "arekinath"
},
{
"collectionURL": "https://github.com",
"cpes": [
"cpe:2.3:a:handnot2:esaml:*:*:*:*:*:*:*:*"
],
"defaultStatus": "affected",
"packageName": "handnot2/esaml",
"packageURL": "pkg:github/handnot2/esaml",
"product": "esaml",
"repo": "https://github.com/handnot2/esaml.git",
"vendor": "handnot2"
},
{
"collectionURL": "https://github.com",
"cpes": [
"cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*"
],
"defaultStatus": "affected",
"packageName": "dropbox/esaml",
"packageURL": "pkg:github/dropbox/esaml",
"product": "esaml",
"repo": "https://github.com/dropbox/esaml.git",
"vendor": "dropbox"
},
{
"collectionURL": "https://github.com",
"cpes": [
"cpe:2.3:a:jump-app:esaml:*:*:*:*:*:*:*:*"
],
"defaultStatus": "affected",
"packageName": "Jump-App/esaml",
"packageURL": "pkg:github/Jump-App/esaml",
"product": "esaml",
"repo": "https://github.com/Jump-App/esaml.git",
"vendor": "Jump-App",
"versions": [
{
"lessThan": "bab85efde7c136911402a881ca55173759467a26",
"status": "affected",
"version": "0",
"versionType": "git"
},
{
"status": "unaffected",
"version": "bab85efde7c136911402a881ca55173759467a26",
"versionType": "git"
}
]
}
],
"configurations": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "The application must use esaml to process SAML messages and run on Erlang/OTP versions before 27. Starting with OTP 27, \u003ctt\u003exmerl_scan\u003c/tt\u003e disables entity expansion by default, which mitigates this vulnerability."
}
],
"value": "The application must use esaml to process SAML messages and run on Erlang/OTP versions before 27. Starting with OTP 27, xmerl_scan disables entity expansion by default, which mitigates this vulnerability."
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:arekinath:esaml:*:*:*:*:*:*:*:*",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:handnot2:esaml:*:*:*:*:*:*:*:*",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:jump-app:esaml:*:*:*:*:*:*:*:*",
"versionEndExcluding": "bab85efde7c136911402a881ca55173759467a26",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
],
"operator": "AND"
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Bryan Lynch"
},
{
"lang": "en",
"type": "coordinator",
"value": "Jonatan M\u00e4nnchen / EEF"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "XML External Entity (XXE) vulnerability in esaml (and its forks) allows an attacker to cause the system to read local files and incorporate their contents into processed SAML documents, and potentially perform SSRF via crafted SAML messages.\u003cp\u003eesaml parses attacker-controlled SAML messages using \u003ctt\u003exmerl_scan:string/2\u003c/tt\u003e before signature verification without disabling XML entity expansion. On Erlang/OTP versions before 27, Xmerl allows entities by default, enabling pre-signature XXE attacks. An attacker can cause the host to read local files (e.g., Kubernetes-mounted secrets) into the SAML document. If the attacker is not a trusted SAML SP, signature verification will fail and the document is discarded, but file contents may still be exposed through logs or error messages.\u003c/p\u003e\u003cp\u003eThis issue affects all versions of esaml, including forks by arekinath, handnot2, and dropbox. Users running on Erlang/OTP 27 or later are not affected due to Xmerl defaulting to entities disabled.\u003c/p\u003e"
}
],
"value": "XML External Entity (XXE) vulnerability in esaml (and its forks) allows an attacker to cause the system to read local files and incorporate their contents into processed SAML documents, and potentially perform SSRF via crafted SAML messages.\n\nesaml parses attacker-controlled SAML messages using xmerl_scan:string/2 before signature verification without disabling XML entity expansion. On Erlang/OTP versions before 27, Xmerl allows entities by default, enabling pre-signature XXE attacks. An attacker can cause the host to read local files (e.g., Kubernetes-mounted secrets) into the SAML document. If the attacker is not a trusted SAML SP, signature verification will fail and the document is discarded, but file contents may still be exposed through logs or error messages.\n\nThis issue affects all versions of esaml, including forks by arekinath, handnot2, and dropbox. Users running on Erlang/OTP 27 or later are not affected due to Xmerl defaulting to entities disabled."
}
],
"impacts": [
{
"capecId": "CAPEC-201",
"descriptions": [
{
"lang": "en",
"value": "CAPEC-201 Serialized Data External Linking"
}
]
}
],
"metrics": [
{
"cvssV4_0": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"baseScore": 6.3,
"baseSeverity": "MEDIUM",
"exploitMaturity": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "NONE",
"vulnConfidentialityImpact": "LOW",
"vulnIntegrityImpact": "NONE",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-611",
"description": "CWE-611 Improper Restriction of XML External Entity Reference",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-04-07T14:38:07.406Z",
"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"shortName": "EEF"
},
"references": [
{
"tags": [
"third-party-advisory",
"related"
],
"url": "https://cna.erlef.org/cves/CVE-2026-28809.html"
},
{
"tags": [
"related"
],
"url": "https://osv.dev/vulnerability/EEF-CVE-2026-28809"
},
{
"tags": [
"patch"
],
"url": "https://github.com/Jump-App/esaml/commit/bab85efde7c136911402a881ca55173759467a26"
}
],
"source": {
"discovery": "EXTERNAL"
},
"title": "XXE in esaml SAML library allows local file read and potential SSRF",
"workarounds": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "Upgrade to Erlang/OTP 27 or later. Starting with OTP 27, \u003ctt\u003exmerl_scan\u003c/tt\u003e disables entity expansion by default, which mitigates this vulnerability without changes to esaml."
}
],
"value": "Upgrade to Erlang/OTP 27 or later. Starting with OTP 27, xmerl_scan disables entity expansion by default, which mitigates this vulnerability without changes to esaml."
}
],
"x_generator": {
"engine": "Vulnogram 1.0.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"assignerShortName": "EEF",
"cveId": "CVE-2026-28809",
"datePublished": "2026-03-23T10:09:29.233Z",
"dateReserved": "2026-03-03T14:40:00.590Z",
"dateUpdated": "2026-04-07T14:38:07.406Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"vulnrichment": {
"containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-28809\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-03-23T15:07:17.488260Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-03-23T15:07:18.519Z\"}}], \"cna\": {\"title\": \"XXE in esaml SAML library allows local file read and potential SSRF\", \"source\": {\"discovery\": \"EXTERNAL\"}, \"credits\": [{\"lang\": \"en\", \"type\": \"finder\", \"value\": \"Bryan Lynch\"}, {\"lang\": \"en\", \"type\": \"coordinator\", \"value\": \"Jonatan M\\u00e4nnchen / EEF\"}], \"impacts\": [{\"capecId\": \"CAPEC-201\", \"descriptions\": [{\"lang\": \"en\", \"value\": \"CAPEC-201 Serialized Data External Linking\"}]}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV4_0\": {\"Safety\": \"NOT_DEFINED\", \"version\": \"4.0\", \"Recovery\": \"NOT_DEFINED\", \"baseScore\": 6.3, \"Automatable\": \"NOT_DEFINED\", \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"valueDensity\": \"NOT_DEFINED\", \"vectorString\": \"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N\", \"exploitMaturity\": \"NOT_DEFINED\", \"providerUrgency\": \"NOT_DEFINED\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"attackRequirements\": \"PRESENT\", \"privilegesRequired\": \"NONE\", \"subIntegrityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"NONE\", \"subAvailabilityImpact\": \"NONE\", \"vulnAvailabilityImpact\": \"NONE\", \"subConfidentialityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"LOW\", \"vulnerabilityResponseEffort\": \"NOT_DEFINED\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"cpes\": [\"cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*\", \"cpe:2.3:a:arekinath:esaml:*:*:*:*:*:*:*:*\", \"cpe:2.3:a:handnot2:esaml:*:*:*:*:*:*:*:*\"], \"vendor\": \"dropbox\", \"product\": \"esaml\", \"packageURL\": \"pkg:hex/esaml\", \"packageName\": \"esaml\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:2.3:a:arekinath:esaml:*:*:*:*:*:*:*:*\"], \"repo\": \"https://github.com/arekinath/esaml.git\", \"vendor\": \"arekinath\", \"product\": \"esaml\", \"packageURL\": \"pkg:github/arekinath/esaml\", \"packageName\": \"arekinath/esaml\", \"collectionURL\": \"https://github.com\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:2.3:a:handnot2:esaml:*:*:*:*:*:*:*:*\"], \"repo\": \"https://github.com/handnot2/esaml.git\", \"vendor\": \"handnot2\", \"product\": \"esaml\", \"packageURL\": \"pkg:github/handnot2/esaml\", \"packageName\": \"handnot2/esaml\", \"collectionURL\": \"https://github.com\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*\"], \"repo\": \"https://github.com/dropbox/esaml.git\", \"vendor\": \"dropbox\", \"product\": \"esaml\", \"packageURL\": \"pkg:github/dropbox/esaml\", \"packageName\": \"dropbox/esaml\", \"collectionURL\": \"https://github.com\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:2.3:a:jump-app:esaml:*:*:*:*:*:*:*:*\"], \"repo\": \"https://github.com/Jump-App/esaml.git\", \"vendor\": \"Jump-App\", \"product\": \"esaml\", \"versions\": [{\"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"bab85efde7c136911402a881ca55173759467a26\", \"versionType\": \"git\"}, {\"status\": \"unaffected\", \"version\": \"bab85efde7c136911402a881ca55173759467a26\", \"versionType\": \"git\"}], \"packageURL\": \"pkg:github/Jump-App/esaml\", \"packageName\": \"Jump-App/esaml\", \"collectionURL\": \"https://github.com\", \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://cna.erlef.org/cves/CVE-2026-28809.html\", \"tags\": [\"third-party-advisory\", \"related\"]}, {\"url\": \"https://osv.dev/vulnerability/EEF-CVE-2026-28809\", \"tags\": [\"related\"]}, {\"url\": \"https://github.com/Jump-App/esaml/commit/bab85efde7c136911402a881ca55173759467a26\", \"tags\": [\"patch\"]}], \"workarounds\": [{\"lang\": \"en\", \"value\": \"Upgrade to Erlang/OTP 27 or later. Starting with OTP 27, xmerl_scan disables entity expansion by default, which mitigates this vulnerability without changes to esaml.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"Upgrade to Erlang/OTP 27 or later. Starting with OTP 27, \u003ctt\u003exmerl_scan\u003c/tt\u003e disables entity expansion by default, which mitigates this vulnerability without changes to esaml.\", \"base64\": false}]}], \"x_generator\": {\"engine\": \"Vulnogram 1.0.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"XML External Entity (XXE) vulnerability in esaml (and its forks) allows an attacker to cause the system to read local files and incorporate their contents into processed SAML documents, and potentially perform SSRF via crafted SAML messages.\\n\\nesaml parses attacker-controlled SAML messages using xmerl_scan:string/2 before signature verification without disabling XML entity expansion. On Erlang/OTP versions before 27, Xmerl allows entities by default, enabling pre-signature XXE attacks. An attacker can cause the host to read local files (e.g., Kubernetes-mounted secrets) into the SAML document. If the attacker is not a trusted SAML SP, signature verification will fail and the document is discarded, but file contents may still be exposed through logs or error messages.\\n\\nThis issue affects all versions of esaml, including forks by arekinath, handnot2, and dropbox. Users running on Erlang/OTP 27 or later are not affected due to Xmerl defaulting to entities disabled.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"XML External Entity (XXE) vulnerability in esaml (and its forks) allows an attacker to cause the system to read local files and incorporate their contents into processed SAML documents, and potentially perform SSRF via crafted SAML messages.\u003cp\u003eesaml parses attacker-controlled SAML messages using \u003ctt\u003exmerl_scan:string/2\u003c/tt\u003e before signature verification without disabling XML entity expansion. On Erlang/OTP versions before 27, Xmerl allows entities by default, enabling pre-signature XXE attacks. An attacker can cause the host to read local files (e.g., Kubernetes-mounted secrets) into the SAML document. If the attacker is not a trusted SAML SP, signature verification will fail and the document is discarded, but file contents may still be exposed through logs or error messages.\u003c/p\u003e\u003cp\u003eThis issue affects all versions of esaml, including forks by arekinath, handnot2, and dropbox. Users running on Erlang/OTP 27 or later are not affected due to Xmerl defaulting to entities disabled.\u003c/p\u003e\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-611\", \"description\": \"CWE-611 Improper Restriction of XML External Entity Reference\"}]}], \"configurations\": [{\"lang\": \"en\", \"value\": \"The application must use esaml to process SAML messages and run on Erlang/OTP versions before 27. Starting with OTP 27, xmerl_scan disables entity expansion by default, which mitigates this vulnerability.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"The application must use esaml to process SAML messages and run on Erlang/OTP versions before 27. Starting with OTP 27, \u003ctt\u003exmerl_scan\u003c/tt\u003e disables entity expansion by default, which mitigates this vulnerability.\", \"base64\": false}]}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*\", \"vulnerable\": true}, {\"criteria\": \"cpe:2.3:a:arekinath:esaml:*:*:*:*:*:*:*:*\", \"vulnerable\": true}, {\"criteria\": \"cpe:2.3:a:handnot2:esaml:*:*:*:*:*:*:*:*\", \"vulnerable\": true}, {\"criteria\": \"cpe:2.3:a:jump-app:esaml:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"bab85efde7c136911402a881ca55173759467a26\"}], \"operator\": \"OR\"}], \"operator\": \"AND\"}], \"providerMetadata\": {\"orgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"shortName\": \"EEF\", \"dateUpdated\": \"2026-04-07T14:38:07.406Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-28809\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-07T14:38:07.406Z\", \"dateReserved\": \"2026-03-03T14:40:00.590Z\", \"assignerOrgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"datePublished\": \"2026-03-23T10:09:29.233Z\", \"assignerShortName\": \"EEF\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…