GHSA-g27r-r6ph-vf5r: Sequoia git Sequoia-git Has Broken Hard Revocation Vulnerability

LOW
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CWE-299
Published
Advisory Summary

GHSA-g27r-r6ph-vf5r is a LOW sequoia-git has broken hard revocation vulnerability (CWE-299: Improper Check for Certificate Revocation) affecting Sequoia git libraries in the crates.io ecosystem. The issue involves sequoia-git has broken hard revocation handling. Remediation is available by upgrading affected packages to version 0.6.0.

GHSA-g27r-r6ph-vf5r at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-g27r-r6ph-vf5r
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-299: Improper Check for Certificate Revocation
Affected Product Sequoia git
Package Ecosystem crates.io
Published Date
Last Updated

How to Fix GHSA-g27r-r6ph-vf5r

To remediate this vulnerability, upgrade all affected Sequoia git dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

sequoia-git fixed: 0.6.0 
Upgrade sequoia-git to 0.6.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for sequoia-git

How to Check if You Are Affected

To determine whether your application is affected by GHSA-g27r-r6ph-vf5r, inspect your project dependencies for Sequoia git:

inspect dependencies for sequoia-git

Analyze the terminal output to locate any version of Sequoia git in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.6.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-299: Improper Check for Certificate Revocation, where the product does not check or incorrectly checks the revocation status of a certificate, which may cause it to use a certificate that has been compromised. In Sequoia git, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Before `sq-git` checks if a commit can be authenticated, it first looks for hard revocations. Because parsing a policy is expensive and a project's policy rarely changes, `sq-git` has an optimization to only check a policy if it hasn't checked it before. It does this by maintaining a set of policies that it had already seen keyed on the policy's hash. Unfortunately, due to a bug the hash was truncated to be 0 bytes and thus only hard revocations in the target commit were considered. Normally this is not a problem as hard revocations are not removed from the signing policy. An attacker could nevertheless exploit this flaw as follows. Consider Alice and Bob who maintain a project together. If Bob's certificate is compromised and Bob issues a hard revocation, Alice can add it to the project's signing policy. An attacker who has access to Bob's key can then create a merge request that strips the hard revocation. If Alice merges Bob's merge request, then the latest commit will not carry the hard revocation, and `sq-git` will not see the hard revocation when authenticating that commit or any following commits. Note: for this attack to be successful, Alice needs to be tricked into merging the malicious MR. If Alice is reviewing MRs, then she is likely to notice changes to the signing policy. Reported-by: Hassan Sheet

GHSA-g27r-r6ph-vf5r Affected Sequoia git Versions

1 component(s)
Fixed Versions:
0.6.0
Product / Package Ecosystem Affected Versions Fixed Version
sequoia-git
 crates.io
< 0.6.0
0.6.0

References

gitlab.com/sequoia-pgp/sequoia... PACKAGE
https://gitlab.com/sequoia-pgp/sequoia-git
gitlab.com/sequoia-pgp/sequoia... WEB
https://gitlab.com/sequoia-pgp/sequoia-git/-/commit/f9c9074bd80023456221f09c3c4ff19957ee9c58
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2026-0109.html

Frequently Asked Questions

What is GHSA-g27r-r6ph-vf5r?
GHSA-g27r-r6ph-vf5r is a security vulnerability in Sequoia git involving sequoia-git has broken hard revocation handling under CWE-299: Improper Check for Certificate Revocation.
Which Sequoia git versions are affected?
Affected versions include releases prior to 0.6.0 across affected packages: sequoia-git.
What version fixes GHSA-g27r-r6ph-vf5r?
Upgrading to 0.6.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is sequoia-git affected?
Yes, sequoia-git is affected in releases prior to 0.6.0. Upgrade your dependency to 0.6.0 or later.
What CWE is associated with GHSA-g27r-r6ph-vf5r?
GHSA-g27r-r6ph-vf5r is classified under CWE-299: Improper Check for Certificate Revocation (The product does not check or incorrectly checks the revocation status of a certificate, which may cause it to use a certificate that has been compromised.).
How can I check crates.io dependencies for GHSA-g27r-r6ph-vf5r?
Run the dependency tree command: 'inspect dependencies for sequoia-git'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-g27r-r6ph-vf5r",
  "modified" : "2026-05-04T22:28:50Z",
  "published" : "2026-05-04T22:28:50Z",
  "aliases" : [ ],
  "summary" : "sequoia-git has broken hard revocation handling",
  "details" : "Before `sq-git` checks if a commit can be authenticated, it first looks for hard revocations.  Because parsing a policy is expensive\nand a project's policy rarely changes, `sq-git` has an optimization to only check a policy if it hasn't checked it before.  It does this by maintaining a set of policies that it had already seen keyed on the policy's hash.  Unfortunately, due to a bug the hash was truncated to be 0 bytes and thus only hard revocations in the target commit were considered.  Normally this is not a problem as hard revocations are not removed from the signing policy.\n\nAn attacker could nevertheless exploit this flaw as follows. Consider Alice and Bob who maintain a project together.  If Bob's\ncertificate is compromised and Bob issues a hard revocation, Alice can add it to the project's signing policy.  An attacker who has\naccess to Bob's key can then create a merge request that strips the hard revocation.  If Alice merges Bob's merge request, then\nthe latest commit will not carry the hard revocation, and `sq-git` will not see the hard revocation when authenticating that commit or any following commits.\n\nNote: for this attack to be successful, Alice needs to be tricked into merging the malicious MR.  If Alice is reviewing MRs, then she is likely to notice changes to the signing policy.\n\nReported-by: Hassan Sheet",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "sequoia-git"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.6.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "PACKAGE",
    "url" : "https://gitlab.com/sequoia-pgp/sequoia-git"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.com/sequoia-pgp/sequoia-git/-/commit/f9c9074bd80023456221f09c3c4ff19957ee9c58"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2026-0109.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-299" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-04T22:28:50Z",
    "nvd_published_at" : null
  }
}