Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-53583— libgit2: Inverted IP SubjectAltName Comparison in OpenSSL Backend

Quick assessment

Affected
libgit2 libgit2
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

libgit2 是一个可移植的 C 语言实现，封装了 Git 核心方法，并以库的形式提供，具备稳定的 API，便于在应用程序中集成 Git 功能。在 1.8.6 和 1.9.5 版本之前， 中的 函数在处理 IP 字面量主机名与证书中 IP 类型 SubjectAltName 扩展项进行比较时，在 GEN_IPADD 分支中错误地使用了取反的 返回值。这导致基于 OpenSSL 的构建版本在 IP 地址匹配时会拒绝连接，而在 IP 地址不匹配时却接受连接。因此，拥有由受信任证书颁发机构（CA）签发的、包含任意 IP

CVSS 6.5 · Medium EPSS 0.19% · P9

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 2

VendorProduct Version RangeStatus
libgit2 libgit2 < 1.8.6 affected
>= 1.9.0, < 1.9.5 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-53583

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
libgit2: Inverted IP SubjectAltName Comparison in OpenSSL Backend
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
证书验证不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
libgit2 libgit2 < 1.8.6 -

II. Public POCs for CVE-2026-53583

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-53583

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-53583 (4)

Vendor Advisories for CVE-2026-53583 (1)

Vendor Pages for CVE-2026-53583 (1)

Same Patch Batch · libgit2 · 2026-08-20 · 5 CVEs total

CVE-2026-53587 7.5 HIGH libgit2 - Unauthenticated network-reachable heap out-of-bounds read in transports/smart_pk
CVE-2026-53586 6.5 MEDIUM libgit2: HTTP transport can leak credentials to an offsite redirect target
CVE-2026-53585 5.3 MEDIUM libgit2: Unbounded Memory Allocation via Delta Object Result-Size Header
CVE-2026-53584 4.3 MEDIUM libgit2: Submodule path traversal

IV. Related Vulnerabilities

Same product: libgit2
Same vendor: libgit2
Same weakness: CWE-295

V. Comments for CVE-2026-53583

No comments yet

Leave a comment