CVE-2026-5466 | THREATINT

Description

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.

PUBLISHED Reserved 2026-04-03 | Published 2026-04-10 | Updated 2026-04-22 | Assigner wolfSSL

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

Problem types

CWE-347 Improper verification of cryptographic signature

Product status

Default status

unaffected

Any version before 5.9.1

affected

Credits

Calif.io in collaboration with Claude and Anthropic Research finder

References

github.com/wolfssl/wolfssl/pull/10102

cve.org (CVE-2026-5466)

nvd.nist.gov (CVE-2026-5466)

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