CVE-2026-53585
Received Received - Intake

Memory Exhaustion in libgit2 via Malicious Delta Objects

Publication date: 2026-08-20

Last updated on: 2026-08-20

Assigner: GitHub, Inc.

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, git_delta_apply in src/libgit2/delta.c trusts the attacker-controlled res_sz value parsed by hdr_sz from a delta object header and passes that amount to git__malloc before validating delta instructions. Malicious pack data supplied through git_clone, git_fetch, git_remote_fetch, git_indexer_append, or a local attacker-supplied repository can use a very small multi-level OFS_DELTA chain to retain extremely large allocations and exhaust memory. This issue is fixed in versions 1.8.6 and 1.9.5.

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Meta Information

Published
2026-08-20
Last Modified
2026-08-20
Generated
2026-08-20
AI Q&A
2026-08-20
EPSS Evaluated
N/A
NVD
CVE-2026-53585
EUVD
EUVD-2026-63548

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
libgit2 libgit2 to 1.8.6 (inc)
libgit2 libgit2 to 1.9.5 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-770 The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

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Executive Summary

This vulnerability in libgit2 versions before 1.8.6 and 1.9.5 involves a memory exhaustion issue. The function git_delta_apply trusts an attacker-controlled size value from a delta object header without validating it first. This allows malicious pack data to trigger extremely large memory allocations through multi-level OFS_DELTA chains, potentially crashing the application.

Detection Guidance

This vulnerability can be detected by checking the version of libgit2 in use. Commands like 'git --version' or inspecting the libgit2 library version in your application dependencies can help. If using a package manager, commands like 'apt list --installed | grep libgit2' or 'rpm -qa | grep libgit2' may identify vulnerable versions.

Impact Analysis

An attacker could exploit this to crash applications using vulnerable libgit2 versions by supplying specially crafted Git repositories or data during clone, fetch, or remote operations. This could lead to denial-of-service conditions, disrupting services that rely on libgit2 for Git functionality.

Compliance Impact

This vulnerability primarily enables denial-of-service attacks through memory exhaustion, which could disrupt system availability. While not directly violating GDPR or HIPAA, such disruptions may impact data access or processing, potentially affecting compliance with availability requirements in these regulations. No direct evidence links this CVE to specific compliance violations.

Mitigation Strategies

Immediately upgrade libgit2 to version 1.8.6 or 1.9.5 or later. If using a package manager, run commands like 'apt upgrade libgit2' or 'yum update libgit2'. For applications embedding libgit2, update the library and recompile the application.

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