libgit2 - Unauthenticated network-reachable heap out-of-bounds read in transports/smart_pkt.c:set_data

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-53587
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-20 19:16:55 UTC
Updated2026-08-20 20:17:34 UTC
Descriptionlibgit2 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

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

Problem Types: CWE-20 | CWE-125 | CWE-126 | CWE-1284 | 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

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Libgit2 Libgit2 affected < 1.8.6 Not specified
CNA Libgit2 Libgit2 affected >= 1.9.0, < 1.9.5 Not specified

References

ReferenceSourceLinkTags
github.com/libgit2/libgit2/releases/tag/v1.8.6 [email protected] github.com
github.com/libgit2/libgit2/commit/affda60c10fcef16723451c0d7dc71b71dc20ad3 [email protected] github.com
github.com/libgit2/libgit2/security/advisories/GHSA-pm24-4jhq-3xvm 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/libgit2/libgit2/commit/2c0ce8c0132ac38ab0db28239462a671e2e5440e [email protected] github.com
github.com/libgit2/libgit2/releases/tag/v1.9.5 [email protected] github.com
github.com/libgit2/libgit2/commit/d7a9fb87f504434e9f45228678953c4fa56e7640 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report