Executive brief
wolfSSL is a security library used by applications to encrypt and protect data. A flaw in its decryption process allows it to accept modified or forged data without realizing it has been tampered with. This could allow an attacker to bypass security checks, potentially leading to the exposure of sensitive information or the acceptance of malicious commands.
Technical details
A vulnerability exists in wolfSSL's EVP layer specifically within the ChaCha20-Poly1305 AEAD decryption path. The function wolfSSL_EVP_CipherFinal (and related finalization functions) fails to compare the computed authentication tag against the expected tag provided by the sender. This improper validation of the integrity check value (CWE-354) means that the library returns plaintext to the calling application even if the ciphertext has been modified. An attacker with adjacent network access could exploit this to inject malicious data or bypass integrity protections. The issue is addressed in wolfSSL version 5.9.1.
Affected products
- wolfSSL wolfSSL versions up to (excluding) 5.9.1
Timeline
- 2026-03-30: other: Fix submitted via pull request 10102
- 2026-04-06: patched: Fix merged into master branch
- 2026-04-10: disclosed: CVE-2026-5479 published