CVE-2023-39969 json
uthenticode signature validation bypass vulnerability
published 2023-08-09 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-43662
- cvss
- 9.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 47%
- public exploits
- 0
- none known
Summary
uthenticode is a small cross-platform library for partially verifying Authenticode digital signatures. Version 1.0.9 of uthenticode hashed the entire file rather than hashing sections by virtual address, in violation of the Authenticode specification. As a result, an attacker could modify code within a binary without changing its Authenticode hash, making it appear valid from uthenticode's perspective. Versions of uthenticode prior to 1.0.9 are not vulnerable to this attack, nor are versions in the 2.x series. By design, uthenticode does not perform full-chain validation. However, the malleability of signature verification introduced in 1.0.9 was an unintended oversight. The 2.x series addresses the vulnerability. Versions prior to 1.0.9 are also not vulnerable, but users are encouraged to upgrade rather than downgrade. There are no workarounds to this vulnerability.
Patch / fix
- trailofbits uthenticode 1.0.9
- github.com/trailofbits/uthenticode@8670b7b commit
- github.com/trailofbits/uthenticode#84 pull request
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 2 y ago
Exploit prediction
0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
| NVD | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected products
- trailofbits uthenticode
Classification
- Weakness
-
- CWE-347 Improper Verification of Cryptographic Signature
References
Sources
- CVE List CVE-2023-39969
- NVD CVE-2023-39969
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