CVE-2026-116585: Go JOSE: Panic during CBC-HMAC processing

Description

Go JOSE provides an implementation of the Javascript Object Signing and Encryption set of standards in Go, including support for JSON Web Encryption (JWE), JSON Web Signature (JWS), and JSON Web Token (JWT) standards. Prior to 4.1.5, decrypting untrusted JWE ciphertext with A128CBC-HS256, A192CBC-HS384, or A256CBC-HS512 can pass an empty ciphertext buffer to CBC-HMAC unpadding. Insufficient validation allows the empty buffer to be indexed, causing a panic and denial of service. Applications that decrypt attacker-controlled ciphertext with one of these content-encryption algorithms are affected. This issue is fixed in version 4.1.5.

Exploitation

Is it being used?

Exploit prediction (EPSS)0.3% · higher than 18% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

GO

go-jose · go-jose

< 4.1.5 · source: vendor