CVE-2026-44452 (GCVE-0-2026-44452)
Vulnerability from cvelistv5
Published
2026-07-16 22:54
Modified
2026-07-17 14:03
Severity ?
VLAI Severity ?
EPSS score ?
Summary
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 8dc37cb, when h2o receives a ClientHello message over TLS or QUIC and it contains a zero-length SNI extension, the h2o server runs over the zero-length hostname while trying to copy the hostname, assuming that it is NULL-terminated. This is a potential denial-of-service attack vector in sense that it might trigger segmentation violation. This issue has been fixed by commit 8dc37cb.
References
| URL | Tags | |||||||
|---|---|---|---|---|---|---|---|---|
|
||||||||
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-44452",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-17T14:03:32.725590Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-17T14:03:52.757Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "h2o",
"vendor": "h2o",
"versions": [
{
"status": "affected",
"version": "\u003c 8dc37cb"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 8dc37cb, when h2o receives a ClientHello message over TLS or QUIC and it contains a zero-length SNI extension, the h2o server runs over the zero-length hostname while trying to copy the hostname, assuming that it is NULL-terminated. This is a potential denial-of-service attack vector in sense that it might trigger segmentation violation. This issue has been fixed by commit 8dc37cb."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 5.9,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-125",
"description": "CWE-125: Out-of-bounds Read",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-170",
"description": "CWE-170: Improper Null Termination",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-16T22:54:42.914Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/h2o/h2o/security/advisories/GHSA-w68q-rqwx-7wvq",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/h2o/h2o/security/advisories/GHSA-w68q-rqwx-7wvq"
},
{
"name": "https://github.com/h2o/h2o/commit/8dc37cb1e6171f7f772667618ea440696fed82c3",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/h2o/h2o/commit/8dc37cb1e6171f7f772667618ea440696fed82c3"
}
],
"source": {
"advisory": "GHSA-w68q-rqwx-7wvq",
"discovery": "UNKNOWN"
},
"title": "h2o is vulnerable to heap overrun"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-44452",
"datePublished": "2026-07-16T22:54:42.914Z",
"dateReserved": "2026-05-06T15:49:25.192Z",
"dateUpdated": "2026-07-17T14:03:52.757Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"vulnrichment": {
"containers": "{\"cna\": {\"title\": \"h2o is vulnerable to heap overrun\", \"problemTypes\": [{\"descriptions\": [{\"cweId\": \"CWE-125\", \"lang\": \"en\", \"description\": \"CWE-125: Out-of-bounds Read\", \"type\": \"CWE\"}]}, {\"descriptions\": [{\"cweId\": \"CWE-170\", \"lang\": \"en\", \"description\": \"CWE-170: Improper Null Termination\", \"type\": \"CWE\"}]}], \"metrics\": [{\"cvssV3_1\": {\"attackComplexity\": \"HIGH\", \"attackVector\": \"NETWORK\", \"availabilityImpact\": \"HIGH\", \"baseScore\": 5.9, \"baseSeverity\": \"MEDIUM\", \"confidentialityImpact\": \"NONE\", \"integrityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"scope\": \"UNCHANGED\", \"userInteraction\": \"NONE\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H\", \"version\": \"3.1\"}}], \"references\": [{\"name\": \"https://github.com/h2o/h2o/security/advisories/GHSA-w68q-rqwx-7wvq\", \"tags\": [\"x_refsource_CONFIRM\"], \"url\": \"https://github.com/h2o/h2o/security/advisories/GHSA-w68q-rqwx-7wvq\"}, {\"name\": \"https://github.com/h2o/h2o/commit/8dc37cb1e6171f7f772667618ea440696fed82c3\", \"tags\": [\"x_refsource_MISC\"], \"url\": \"https://github.com/h2o/h2o/commit/8dc37cb1e6171f7f772667618ea440696fed82c3\"}], \"affected\": [{\"vendor\": \"h2o\", \"product\": \"h2o\", \"versions\": [{\"version\": \"\u003c 8dc37cb\", \"status\": \"affected\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-07-16T22:54:42.914Z\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 8dc37cb, when h2o receives a ClientHello message over TLS or QUIC and it contains a zero-length SNI extension, the h2o server runs over the zero-length hostname while trying to copy the hostname, assuming that it is NULL-terminated. This is a potential denial-of-service attack vector in sense that it might trigger segmentation violation. This issue has been fixed by commit 8dc37cb.\"}], \"source\": {\"advisory\": \"GHSA-w68q-rqwx-7wvq\", \"discovery\": \"UNKNOWN\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-44452\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-07-17T14:03:32.725590Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-07-17T14:03:45.541Z\"}}]}",
"cveMetadata": "{\"cveId\": \"CVE-2026-44452\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"state\": \"PUBLISHED\", \"assignerShortName\": \"GitHub_M\", \"dateReserved\": \"2026-05-06T15:49:25.192Z\", \"datePublished\": \"2026-07-16T22:54:42.914Z\", \"dateUpdated\": \"2026-07-17T14:03:52.757Z\"}",
"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…