Name: CVE-2026-5466: Improper Verification of Cryptographic Signature
Creator: Rapid7
Published: 2026-04-10T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-5466, CVSS 8.1, EPSS 0.00011

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.

CVSS Details

CVSS 4.0 Base Score: 7.6 (HIGH)
CVSS 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
CVSS 3.1 Base Score: 8.1
CVSS 3.1 Vector: (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Alpine Linux	—	Upgrade wolfssl	May 29, 2026	Apr 10, 2026

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CVSS Details

Covered by Rapid7

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