How severe is CVE-2026-12681?

No CVSS score has been assigned to CVE-2026-12681 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-12681?

CVE-2026-12681 affects the following packages: github.com/google/go-attestation (Go). Ecosystems affected: Go.

How do I fix CVE-2026-12681?

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 CVE-2026-12681 is resolved across your whole dependency graph.

How do I detect CVE-2026-12681 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/google/go-attestation, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-12681 if there is no patch (or I can't update yet)?

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.

Is CVE-2026-12681 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-12681 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-12681?

CVE-2026-12681 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 18th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-12681?

CVE-2026-12681 is classified as CWE-1285 (CWE-1285). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-12681 published, and has it been updated?

CVE-2026-12681 was published on June 24, 2026 and was last updated on August 29, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

CVE-2026-12681 — go-attestation

Fix: google/go-attestation@b6e905e

CVE-2026-12681 is a CWE-1285 vulnerability in github.com/google/go-attestation. A fix is available for github.com/google/go-attestation — see the affected versions and patch details below.

Go-Attestation: Hash injection into trusted measurement list via unskipped SignatureHeaderSize vendor bytes in parseEfiSignatureList()

Also known asGHSA-9r4w-jg96-92mvGO-2026-5298

Published

Jun 24, 2026

Updated

Aug 29, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 14, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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 CVE-2026-12681.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs18th percentile — riskier than 18% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐹github.com/google/go-attestation

Real-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: SignatureHeaderSize must not exceed remaining list space
Skip SignatureHeaderSize bytes before both entry loops
Regression test: TestParseEfiSignatureListNonZeroSignatureHeaderSize

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/google/go-attestation`	all versions	0.6.1`go get github.com/google/go-attestation@v0.6.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/google/go-attestation, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 CVE-2026-12681 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.

Frequently Asked Questions

## 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 remo