WireGuard wg(4) Driver MAC Verification Bypass (CVE-2026-58085)
CVE-2026-58085 Published on August 19, 2026
Missing MAC validation in wg(4) packet decryption
After dispatching a decrypt operation to OCF and receiving the result, the wg(4) driver failed to check whether the MAC verification step succeeded. The driver thus silently accepted packets with an invalid Poly1305 authentication tag.
A remote attacker who can send UDP packets to a WireGuard endpoint, and who can guess the bounds of the receiver's replay window, can inject forged or modified transport data packets into the tunnel.
A remote attacker who can intercept WireGuard packets bound for a FreeBSD host can modify the ciphertext and authenticated data without detection by the receiver.
Weakness Type
Improper Verification of Cryptographic Signature
The software does not verify, or incorrectly verifies, the cryptographic signature for data.
Products Associated with CVE-2026-58085
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Affected Versions
FreeBSD:- Version 15.1-RELEASE and below p2 is affected.
- Version 15.0-RELEASE and below p12 is affected.
- Version 14.4-RELEASE and below p8 is affected.