CVE-2026-5466 PUBLISHED

wc_VerifyEccsiHash missing sanity check

Assigner: wolfSSL
Reserved: 03.04.2026 Published: 10.04.2026 Updated: 10.04.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS Score: 7.6

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Adjacent	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	Present	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	wolfSSL
Product	wolfSSL
Versions	Default: unaffected affected from 0 to 5.9.1 (excl.)

Credits

Calif.io in collaboration with Claude and Anthropic Research finder

References

https://github.com/wolfssl/wolfssl/pull/10102

Problem Types

CWE-347 Improper verification of cryptographic signature CWE