CVE-2026-107579 (GCVE-0-2026-107579)
Vulnerability from cvelistv5
Published
2026-10-08 11:47
Modified
2026-10-08 14:18
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Summary
Inefficient algorithmic complexity in the bounce and complaint processing of Progressive Robot hMailServer 6.3.4 and 6.3.5 allows a remote unauthenticated attacker to stop mail delivery by sending messages, when bounce processing or complaint processing is enabled or a mailing list is managed by the server (none is by default). The readers of incoming delivery status notifications (RFC 3464) and abuse feedback reports (RFC 5965) removed the blank lines at the start of the returned headers part two bytes at a time, copying the rest of the part each time, so their work grew with the square of the number of blank lines. A message shaped like such a report, whose headers part begins with a very large number of blank lines within the reader's 2 MB limit, keeps a delivery thread busy for over a minute while it is delivered, and a few such messages a minute keep every delivery thread busy.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Progressive Robot Ltd | hMailServer |
Version: 6.3.4 ≤ |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-107579",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-10-08T14:18:11.248365Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-10-08T14:18:19.902Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "hMailServer",
"repo": "https://gitlab.com/hmailserver/hmailserver",
"vendor": "Progressive Robot Ltd",
"versions": [
{
"lessThan": "6.3.6",
"status": "affected",
"version": "6.3.4",
"versionType": "semver"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Found in the hMailServer project\u0027s own security review (Progressive Robot Ltd)"
}
],
"descriptions": [
{
"lang": "en",
"value": "Inefficient algorithmic complexity in the bounce and complaint processing of Progressive Robot hMailServer 6.3.4 and 6.3.5 allows a remote unauthenticated attacker to stop mail delivery by sending messages, when bounce processing or complaint processing is enabled or a mailing list is managed by the server (none is by default). The readers of incoming delivery status notifications (RFC 3464) and abuse feedback reports (RFC 5965) removed the blank lines at the start of the returned headers part two bytes at a time, copying the rest of the part each time, so their work grew with the square of the number of blank lines. A message shaped like such a report, whose headers part begins with a very large number of blank lines within the reader\u0027s 2 MB limit, keeps a delivery thread busy for over a minute while it is delivered, and a few such messages a minute keep every delivery thread busy."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-407",
"description": "CWE-407: Inefficient Algorithmic Complexity",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-08T11:47:06.084Z",
"orgId": "ceab7361-8a18-47b1-92ba-4d7d25f6715a",
"shortName": "GitLab"
},
"references": [
{
"url": "https://gitlab.com/hmailserver/hmailserver/-/work_items/70"
},
{
"url": "https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"
}
],
"solutions": [
{
"lang": "en",
"value": "Upgrade to hMailServer 6.3.6, whose report readers cut the leading blank lines off once. Until then, turn bounce processing, complaint processing and list management off (the default)."
}
],
"title": "Inefficient Algorithmic Complexity in hMailServer"
}
},
"cveMetadata": {
"assignerOrgId": "ceab7361-8a18-47b1-92ba-4d7d25f6715a",
"assignerShortName": "GitLab",
"cveId": "CVE-2026-107579",
"datePublished": "2026-10-08T11:47:06.084Z",
"dateReserved": "2026-10-08T10:52:00.639Z",
"dateUpdated": "2026-10-08T14:18:19.902Z",
"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-2026-107579\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-10-08T14:18:11.248365Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-10-08T14:18:16.724Z\"}}], \"cna\": {\"title\": \"Inefficient Algorithmic Complexity in hMailServer\", \"credits\": [{\"lang\": \"en\", \"type\": \"finder\", \"value\": \"Found in the hMailServer project\u0027s own security review (Progressive Robot Ltd)\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"repo\": \"https://gitlab.com/hmailserver/hmailserver\", \"vendor\": \"Progressive Robot Ltd\", \"product\": \"hMailServer\", \"versions\": [{\"status\": \"affected\", \"version\": \"6.3.4\", \"lessThan\": \"6.3.6\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}], \"solutions\": [{\"lang\": \"en\", \"value\": \"Upgrade to hMailServer 6.3.6, whose report readers cut the leading blank lines off once. Until then, turn bounce processing, complaint processing and list management off (the default).\"}], \"references\": [{\"url\": \"https://gitlab.com/hmailserver/hmailserver/-/work_items/70\"}, {\"url\": \"https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Inefficient algorithmic complexity in the bounce and complaint processing of Progressive Robot hMailServer 6.3.4 and 6.3.5 allows a remote unauthenticated attacker to stop mail delivery by sending messages, when bounce processing or complaint processing is enabled or a mailing list is managed by the server (none is by default). The readers of incoming delivery status notifications (RFC 3464) and abuse feedback reports (RFC 5965) removed the blank lines at the start of the returned headers part two bytes at a time, copying the rest of the part each time, so their work grew with the square of the number of blank lines. A message shaped like such a report, whose headers part begins with a very large number of blank lines within the reader\u0027s 2 MB limit, keeps a delivery thread busy for over a minute while it is delivered, and a few such messages a minute keep every delivery thread busy.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-407\", \"description\": \"CWE-407: Inefficient Algorithmic Complexity\"}]}], \"providerMetadata\": {\"orgId\": \"ceab7361-8a18-47b1-92ba-4d7d25f6715a\", \"shortName\": \"GitLab\", \"dateUpdated\": \"2026-10-08T11:47:06.084Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-107579\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-10-08T14:18:19.902Z\", \"dateReserved\": \"2026-10-08T10:52:00.639Z\", \"assignerOrgId\": \"ceab7361-8a18-47b1-92ba-4d7d25f6715a\", \"datePublished\": \"2026-10-08T11:47:06.084Z\", \"assignerShortName\": \"GitLab\"}",
"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…