---
cve: "CVE-2026-53587"
severity: "HIGH"
cvss: 7.5
epss: "0.5%"
vendor: "libgit2"
kev: false
exploited: false
published: "2026-08-20 19:16:55"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T10:59:20+02:00"
---

# CVE-2026-53587

> 7.5 HIGH · 🧪 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, libgit2 performs a fixed-size strncmp in set_data in src/libgit2/transports/smart_pkt.c without first verifying that the smart-protocol pkt-line capability buffer contains 14 bytes. A malicious Git server can make bytes after the pkt-line complete object-format=, causing format_str to advance beyond the pkt-line and the following memchr length calculation to underflow. The resulting heap out-of-bounds walk can crash a client during the first refs-advertisement packet over HTTP, HTTPS, SSH, or the Git protocol. 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:N/I:N/A:H
```

| 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 | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- 5853918c4c6a7b12f8becf4bd11ff4362ebb9020 (Commit)
- f7a4071c766ceea3915415e22134cbe3e581c420 (Commit)

## Referenzen

- <https://github.com/libgit2/libgit2/security/advisories/GHSA-pm24-4jhq-3xvm>
- <https://github.com/libgit2/libgit2/commit/2c0ce8c0132ac38ab0db28239462a671e2e5440e>
- <https://github.com/libgit2/libgit2/commit/affda60c10fcef16723451c0d7dc71b71dc20ad3>
- <https://github.com/libgit2/libgit2/commit/d7a9fb87f504434e9f45228678953c4fa56e7640>
- <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-2026-53587) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_