GHSA-9r4w-jg96-92mv is a medium-severity (CVSS 6.8) CWE-1285 vulnerability in github.com/google/go-attestation. O3 Security confirms whether GHSA-9r4w-jg96-92mv is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Go-Attestation: Hash injection into trusted measurement list via unskipped SignatureHeaderSize vendor bytes in parseEfiSignatureList()
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-9r4w-jg96-92mv.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-9r4w-jg96-92mv plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 0 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/google/go-attestationReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
parseEfiSignatureList() in attest/internal/events.go does not skip
SignatureHeaderSize vendor bytes before reading EFI_SIGNATURE_LIST
signature entries, violating UEFI specification section 31.4.1.
Impact
For hashSHA256SigGUID lists, attacker-controlled vendor header bytes are appended directly to the trusted SHA256 hash list. A crafted TPM event log can inject arbitrary SHA256 hashes into the verifier's trusted measurement database, allowing a remote attestation verifier to accept a compromised boot state as legitimate — breaking the core integrity guarantee of remote attestation.
Root Cause
After binary.Read(&signatures.Header) reads 28 bytes, buf points to the start of the SignatureHeaderSize vendor bytes. Both entry loops start at sigOffset := 0 instead of sigOffset := SignatureHeaderSize, causing vendor bytes to be read as signature entries.
Affected versions
All versions through commit f877374 (2026-05-15).
Fix
Pull request: https://github.com/google/go-attestation/pull/502
- Add bound check:
SignatureHeaderSizemust not exceed remaining list space - Skip
SignatureHeaderSizebytes before both entry loops - Regression test:
TestParseEfiSignatureListNonZeroSignatureHeaderSize
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/google/go-attestation | all versions | 0.6.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/google/go-attestation. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/google/go-attestation to 0.6.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9r4w-jg96-92mv is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-9r4w-jg96-92mv is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-9r4w-jg96-92mv. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-9r4w-jg96-92mv in your dependencies?
O3 detects GHSA-9r4w-jg96-92mv across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.