Is CVE-2026-5466 actively exploited?

A proof-of-concept exploit is publicly available for CVE-2026-5466, but active exploitation has not been confirmed.

Can CVE-2026-5466 be exploited remotely?

Partially. CVE-2026-5466 requires adjacent network access (same network segment) to exploit.

What is the CVSS score of CVE-2026-5466?

CVE-2026-5466 has a CVSS score of 7.6 (HIGH).

HOME VULNERABILITIESCVE-2026-5466

HIGHPOC

CVE-2026-5466

CWE-347Published: April 10, 2026· Updated: Apr 13, 2026

7.6

CVSS v3.1

EPSS:0.01%probability of exploitation in 30 daysPercentile:1.5th

Official 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.

NVD Source

Technical Analysis

CVE-2026-5466 requires adjacent network access, limiting remote exploitation but still posing risk in shared or local network environments.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A proof-of-concept (PoC) exploit exists for CVE-2026-5466. While not yet confirmed in active campaigns, the availability of PoC code increases exploitation risk substantially.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorAdjacent

Attack ComplexityLow

Privileges Req.None

User InteractionNone

ScopeX

Impact

Confidentiality

Integrity

Availability

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