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go-billy: Lack of depth and cycle detection in symlink resolution may lead to infinite loops and resource exhaustion

Moderate severity GitHub Reviewed Published May 11, 2026 in go-git/go-billy • Updated Jun 9, 2026

Package

gomod github.com/go-git/go-billy/v5 (Go)

Affected versions

< 5.9.0

Patched versions

5.9.0
gomod github.com/go-git/go-billy/v6 (Go)
< 6.0.0-alpha.1
6.0.0-alpha.1

Description

Impact

Multiple components may improperly handle crafted or malformed input, resulting in panics, infinite loops, uncontrolled recursion, or excessive resource consumption.

These issues arise from insufficient validation and missing safety mechanisms such as cycle detection, recursion limits, or defensive handling of unexpected states when processing untrusted repository data and filesystem structures.

Patches

Users should upgrade to a patched version in order to mitigate this vulnerability. Versions prior to v5 are likely to be affected, users are recommended to upgrade to a supported go-billy version.

Credits

Thanks to @faran66 for finding and reporting this issue privately to the go-git project. 🙇

References

@pjbgf pjbgf published to go-git/go-billy May 11, 2026
Published to the GitHub Advisory Database May 13, 2026
Reviewed May 13, 2026
Published by the National Vulnerability Database Jun 1, 2026
Last updated Jun 9, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(22nd percentile)

Weaknesses

Uncontrolled Recursion

The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. Learn more on MITRE.

Loop with Unreachable Exit Condition ('Infinite Loop')

The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. Learn more on MITRE.

CVE ID

CVE-2026-44740

GHSA ID

GHSA-m3xc-h892-ggx6

Source code

Credits

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