GHSA-f5c9-hcxw-8f5v: 
Rust vulnerability analysis and mitigation

Summary

revoke_certificate held the certificate store write lock while waiting for the revocation list write lock; check_certificate_status held a revocation list read lock while waiting for the store read lock. Overlapping calls wait on each other forever, and every later call needing either lock waits too: the X509CertificateManager stops answering until the process restarts. No data is disclosed or changed.

Impact

Availability only. The manager is a public library API; no caller inside the crate routes network input to it, so reachability depends on an integrator exposing revocation and status checks concurrently.

Affected versions

>= 0.4.0, < 0.4.43; >= 0.5.0-rc1, <= 0.5.0-rc27; >= 0.6.0-rc41, <= 0.6.0-rc42. Not affected: 0.1.1, 0.2.0, 0.3.0 (no x509_signing.rs), 0.5.0-rc31 and later, 0.6.0-rc45 and later. Measured by searching src/server/security/x509_signing.rs of 70 of 70 published crate files for the two lock shapes that form the cycle: exactly 27 published versions contain them (0.4.0-0.4.7, 0.4.22, 0.4.24, 0.4.25, 0.4.28, 0.4.29, 0.4.30, 0.4.33, 0.4.34, 0.4.40, 0.4.41, 0.4.42; 0.5.0-rc1, rc18, rc19, rc25, rc26, rc27; 0.6.0-rc41, rc42). The 40 other files that contain the file do not. A deadlock test written for the fix fails on the old 0.4.x code (10 s timeout) and passes after. Unpublished versions in the ranges are placed by source order only.

Patches

Fixed in 0.4.43; the 0.5 and 0.6 lines were already fixed in 0.5.0-rc31 and 0.6.0-rc45. Note: 0.4.43 is a patch release that also moves the optional passkeys feature from passkey/passkey-client 0.4 to 0.6 and coset 0.3 to 0.4 (to clear RUSTSEC-2026-0387). Code that names passkey types directly must adapt.

Workarounds

None short of not calling revoke and status checks concurrently; restart a hung process.