What’s Vulnerable › Vulnerabilities

CVE-2023-40012: uthenticode EKU validation bypass

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-08-09 · updated 2026-06-17
• Weakness: CWE-325

Description

uthenticode is a small cross-platform library for partially verifying Authenticode digital signatures. Versions of uthenticode prior to the 2.x series did not check Extended Key Usages in certificates, in violation of the Authenticode X.509 certificate profile. As a result, a malicious user could produce a "signed" PE file that uthenticode would verify and consider valid using an X.509 certificate that isn't entitled to produce code signatures (e.g., a SSL certificate). By design, uthenticode does not perform full-chain validation. However, the absence of EKU validation was an unintended oversight. The 2.0.0 release series includes EKU checks. There are no workarounds to this vulnerability.

Affected products

• trailofbits uthenticode: before 2.0.0 — fixed in 2.0.0

How to fix

Upgrade to a fixed version: trailofbits uthenticode 2.0.0. Check the vendor advisory for mitigations.

References

• https://github.com/trailofbits/uthenticode/commit/caeb1eb62412605f71bd96ce9bb9420644b6db53
• https://github.com/trailofbits/uthenticode/pull/78
• https://github.com/trailofbits/uthenticode/security/advisories/GHSA-gm2f-j4rj-6xqj
• https://github.com/trailofbits/uthenticode/commit/caeb1eb62412605f71bd96ce9bb9420644b6db53
• https://github.com/trailofbits/uthenticode/pull/78
• https://github.com/trailofbits/uthenticode/security/advisories/GHSA-gm2f-j4rj-6xqj

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