---
cve: "CVE-2026-53583"
severity: "MEDIUM"
cvss: 6.5
epss: "0.2%"
vendor: "libgit2"
kev: false
exploited: false
published: "2026-08-20 19:16:54"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T12:20:04+02:00"
---

# CVE-2026-53583

> 6.5 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Gering | warn |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- 5853918c4c6a7b12f8becf4bd11ff4362ebb9020 (Commit)
- f7a4071c766ceea3915415e22134cbe3e581c420 (Commit)

## Referenzen

- <https://github.com/libgit2/libgit2/security/advisories/GHSA-h7gc-w2gg-p9xp>
- <https://github.com/libgit2/libgit2/commit/647dcb432980b84ede4cb5a008bbd1ccb4ead03d>
- <https://github.com/libgit2/libgit2/commit/c2aa35409ee0e6515df64da49750f13a0a42c47f>
- <https://github.com/libgit2/libgit2/commit/ef086bc3e4eedf62be38a910381aae24d49871ff>
- <https://github.com/libgit2/libgit2/releases/tag/v1.8.6>
- <https://github.com/libgit2/libgit2/releases/tag/v1.9.5>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-53583) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_