MediumFix available
libgit2 — security advisory
libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, verify_server_cert in src/libgit2/streams/openssl.c uses an inverted !!memcmp result in the GEN_IPADD branch when comparing an IP-literal host with a certificate IP SubjectAltName. OpenSSL builds reject matching IP addresses and accept mismatched IP addresses, allowing a network attacker with a CA-trusted certificate containing any IP SubjectAltName to intercept libgit2 connections to IP-literal HTTPS URLs. DNS SubjectAltName validation and non-OpenSSL TLS backends are not affected. This issue is fixed in versions 1.8.6 and 1.9.5.
- Products
- libgit2
- Affected versions
- 0.19.0-2, 0.19.0-2ubuntu0.4, 0.19.0-2ubuntu0.4+esm1, 0.19.0-2ubuntu0.4+esm2, 0.22.2-2, 0.23.1-1, 0.24.1-2, 0.24.1-2ubuntu0.2, 0.24.1-2ubuntu0.2+esm1, 0.24.1-2ubuntu0.2+esm2, 0.24.1-2ubuntu0.2+esm3, 0.24.1-2ubuntu0.2+esm4, 0.25.1+really0.24.6-1, 0.26.0+dfsg.1-1.1, 0.26.0+dfsg.1-1.1build1, 0.26.0+dfsg.1-1.1ubuntu0.2, 0.26.0+dfsg.1-1.1ubuntu0.2+esm1, 0.26.0+dfsg.1-1.1ubuntu0.2+esm2, 0.26.0+dfsg.1-1.1ubuntu0.2+esm3, 0.27.7+dfsg.1-0.2build1, 0.28.3+dfsg.1-1, 0.28.3+dfsg.1-1ubuntu1, 0.28.4+dfsg.1-2, 0.28.4+dfsg.1-2ubuntu0.1, 0.28.4+dfsg.1-2ubuntu0.1+esm1, 0.28.4+dfsg.1-2ubuntu0.1+esm2, 1.1.0+dfsg.1-4, 1.1.0+dfsg.1-4.1, 1.1.0+dfsg.1-4.1build1, 1.1.0+dfsg.1-4.1ubuntu0.1, 1.1.0+dfsg.1-4.1ubuntu0.1+esm1, 1.1.0+dfsg.1-4.1ubuntu0.1+esm2, 1.5.1+ds-1ubuntu1, 1.7.1+ds-2ubuntu1, 1.7.2+ds-1ubuntu1, 1.7.2+ds-1ubuntu2, 1.7.2+ds-1ubuntu3, 1.7.2+ds-1ubuntu3.1, 1.7.2+ds-1ubuntu3.2, 1.9.0+ds-2ubuntu2, 1.9.1+ds-1ubuntu1, 1.9.1+ds-1ubuntu1.1, 1.9.1+ds-1ubuntu1.2
- Fixed versions
- 1.7.2+ds-1ubuntu3.3, 1.9.1+ds-1ubuntu1.3
- CVEs
- CVE-2026-53583
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 28 Oct 2026, 10:04 UTC · Revision 1
Source evidence
libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, verify_server_cert in src/libgit2/streams/openssl.c uses an inverted !!memcmp result in the GEN_IPADD branch when comparing an IP-literal host with a certificate IP SubjectAltName. OpenSSL builds reject matching IP addresses and accept mismatched IP addresses, allowing a network attacker with a CA-trusted certificate containing any IP SubjectAltName to intercept libgit2 connections to IP-literal HTTPS URLs. DNS SubjectAltName validation and non-OpenSSL TLS backends are not affected. This issue is fixed in versions 1.8.6 and 1.9.5.
osv:UBUNTU-CVE-2026-53583
libgit2
Fixed versions: Not specified
libgit2
Fixed versions: Not specified
libgit2
Fixed versions: Not specified
libgit2
Fixed versions: Not specified
libgit2
Fixed versions: Not specified
libgit2
Fixed versions: 1.7.2+ds-1ubuntu3.3
libgit2
Fixed versions: 1.9.1+ds-1ubuntu1.3
Complete source record
{
"id": "78e1891d032b7cb0283b062c09093cacb5e75437696755498d3424e7099a0e67",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-53583",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-53583",
"summary": "libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, verify_server_cert in src/libgit2/streams/openssl.c uses an inverted !!memcmp result in the GEN_IPADD branch when comparing an IP-literal host with a certificate IP SubjectAltName. OpenSSL builds reject matching IP addresses and accept mismatched IP addresses, allowing a network attacker with a CA-trusted certificate containing any IP SubjectAltName to intercept libgit2 connections to IP-literal HTTPS URLs. DNS SubjectAltName validation and non-OpenSSL TLS backends are not affected. This issue is fixed in versions 1.8.6 and 1.9.5.",
"evidence": "osv:UBUNTU-CVE-2026-53583",
"products": [
{
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{
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"evidence": "/affected/0/versions"
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{
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"evidence": "/affected/0/versions"
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{
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{
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{
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{
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{
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{
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{
"value": "0.26.0+dfsg.1-1.1build1",
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{
"value": "0.26.0+dfsg.1-1.1ubuntu0.2",
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{
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{
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{
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{
"value": "0.27.7+dfsg.1-0.2build1",
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{
"value": "0.28.3+dfsg.1-1",
"evidence": "/affected/3/versions"
},
{
"value": "0.28.3+dfsg.1-1ubuntu1",
"evidence": "/affected/3/versions"
},
{
"value": "0.28.4+dfsg.1-2",
"evidence": "/affected/3/versions"
},
{
"value": "0.28.4+dfsg.1-2ubuntu0.1",
"evidence": "/affected/3/versions"
},
{
"value": "0.28.4+dfsg.1-2ubuntu0.1+esm1",
"evidence": "/affected/3/versions"
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{
"value": "0.28.4+dfsg.1-2ubuntu0.1+esm2",
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"name": {
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"evidence": "/affected/4/package/name"
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"affected_versions": [
{
"value": "1.1.0+dfsg.1-4",
"evidence": "/affected/4/versions"
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{
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"evidence": "/affected/4/versions"
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{
"value": "1.1.0+dfsg.1-4.1build1",
"evidence": "/affected/4/versions"
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{
"value": "1.1.0+dfsg.1-4.1ubuntu0.1",
"evidence": "/affected/4/versions"
},
{
"value": "1.1.0+dfsg.1-4.1ubuntu0.1+esm1",
"evidence": "/affected/4/versions"
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{
"value": "1.1.0+dfsg.1-4.1ubuntu0.1+esm2",
"evidence": "/affected/4/versions"
}
]
},
{
"name": {
"value": "libgit2",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.7.2+ds-1ubuntu3.3",
"evidence": "/affected/5/ranges"
}
],
"affected_versions": [
{
"value": "1.5.1+ds-1ubuntu1",
"evidence": "/affected/5/versions"
},
{
"value": "1.7.1+ds-2ubuntu1",
"evidence": "/affected/5/versions"
},
{
"value": "1.7.2+ds-1ubuntu1",
"evidence": "/affected/5/versions"
},
{
"value": "1.7.2+ds-1ubuntu2",
"evidence": "/affected/5/versions"
},
{
"value": "1.7.2+ds-1ubuntu3",
"evidence": "/affected/5/versions"
},
{
"value": "1.7.2+ds-1ubuntu3.1",
"evidence": "/affected/5/versions"
},
{
"value": "1.7.2+ds-1ubuntu3.2",
"evidence": "/affected/5/versions"
}
]
},
{
"name": {
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"evidence": "/affected/6/package/name"
},
"prerequisites": [],
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{
"value": "1.9.1+ds-1ubuntu1.3",
"evidence": "/affected/6/ranges"
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],
"affected_versions": [
{
"value": "1.9.0+ds-2ubuntu2",
"evidence": "/affected/6/versions"
},
{
"value": "1.9.1+ds-1ubuntu1",
"evidence": "/affected/6/versions"
},
{
"value": "1.9.1+ds-1ubuntu1.1",
"evidence": "/affected/6/versions"
},
{
"value": "1.9.1+ds-1ubuntu1.2",
"evidence": "/affected/6/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2026-53583",
"aliases": [
"UBUNTU-CVE-2026-53583"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"
},
{
"type": "Ubuntu",
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"affected": [
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},
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],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"
},
"ecosystem_specific": {
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{
"binary_name": "libgit2-0",
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}
]
}
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{
"ranges": [
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"ecosystem": "Ubuntu:Pro:16.04:LTS"
},
"versions": [
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"0.23.1-1",
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"0.24.1-2ubuntu0.2+esm1",
"0.24.1-2ubuntu0.2+esm2",
"0.24.1-2ubuntu0.2+esm3",
"0.24.1-2ubuntu0.2+esm4"
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"0.26.0+dfsg.1-1.1",
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"0.26.0+dfsg.1-1.1ubuntu0.2",
"0.26.0+dfsg.1-1.1ubuntu0.2+esm1",
"0.26.0+dfsg.1-1.1ubuntu0.2+esm2",
"0.26.0+dfsg.1-1.1ubuntu0.2+esm3"
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"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libgit2-26",
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}
]
}
},
{
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"package": {
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"0.28.4+dfsg.1-2ubuntu0.1+esm1",
"0.28.4+dfsg.1-2ubuntu0.1+esm2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libgit2-28",
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]
}
},
{
"ranges": [
{
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},
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"1.1.0+dfsg.1-4.1ubuntu0.1+esm2"
],
"database_specific": {
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},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libgit2-1.1",
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},
{
"binary_name": "libgit2-fixtures",
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}
]
}
},
{
"ranges": [
{
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{
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},
{
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}
],
"package": {
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},
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"database_specific": {
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},
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},
{
"binary_name": "libgit2-fixtures",
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],
"availability": "No subscription required"
}
},
{
"ranges": [
{
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"events": [
{
"introduced": "0"
},
{
"fixed": "1.9.1+ds-1ubuntu1.3"
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}
],
"package": {
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"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
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"1.9.1+ds-1ubuntu1",
"1.9.1+ds-1ubuntu1.1",
"1.9.1+ds-1ubuntu1.2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53583.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libgit2-1.9",
"binary_version": "1.9.1+ds-1ubuntu1.3"
},
{
"binary_name": "libgit2-fixtures",
"binary_version": "1.9.1+ds-1ubuntu1.3"
}
],
"availability": "No subscription required"
}
}
],
"modified": "2026-10-08T19:48:31.335435982Z",
"provider": "osv",
"upstream": [
"CVE-2026-53583"
],
"references": [
"https://ubuntu.com/security/CVE-2026-53583",
"https://www.cve.org/CVERecord?id=CVE-2026-53583",
"https://github.com/libgit2/libgit2/security/advisories/GHSA-h7gc-w2gg-p9xp",
"https://ubuntu.com/security/notices/USN-8907-1"
]
},
"related_cves": [
{
"value": "CVE-2026-53583",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 104559,
"published_at": "2026-08-20T19:16:00+00:00"
}