CVE-2026-53587

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, 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.

Affected Software

VendorProductVersion RangeStatus
libgit2libgit2< 1.8.6affected
libgit2libgit2>= 1.9.0, < 1.9.5affected

Weaknesses

  • CWE-20: CWE-20: Improper Input Validation
  • CWE-125: CWE-125: Out-of-bounds Read
  • CWE-126: CWE-126: Buffer Over-read
  • CWE-1284: CWE-1284: Improper Validation of Specified Quantity in Input

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: yes
    • Technical Impact: partial

Additional References

References