CVE-2026-5466
wc_VerifyEccsiHash missing sanity check
Severity Score
7.6
*CVSS v4
Exploit Likelihood
*EPSS
Affected Versions
*CPE
Public Exploits
0
*Multiple Sources
Exploited in Wild
-
*KEV
Decision
Track*
*SSVC
Descriptions
wolfSSL's ECCSI signature verifier `wc_VerifyEccsiHash` decodes the `r` and `s` scalars from the signature blob via `mp_read_unsigned_bin` with no check that they lie in `[1, q-1]`. A crafted forged signature could verify against any message for any identity, using only publicly-known constants.
*Credits:
Calif.io in collaboration with Claude and Anthropic Research
CVSS Scores
Attack Vector
Attack Complexity
Attack Requirements
Privileges Required
User Interaction
System
Vulnerable | Subsequent
Confidentiality
Integrity
Availability
* Common Vulnerability Scoring System
SSVC
- Decision:Track*
Exploitation
Automatable
Tech. Impact
* Organization's Worst-case Scenario
Timeline
- 2026-04-03 CVE Reserved
- 2026-04-10 CVE Published
- 2026-04-22 CVE Updated
- 2026-05-12 EPSS Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
- CWE-347: Improper Verification of Cryptographic Signature