{"id":"CVE-2020-8929","aliases":["GHSA-g5vf-v6wf-7w2r","PYSEC-2020-142"],"url":"https://o3.security/vulnerability/CVE-2020-8929","summary":"Ciphertext Malleability Issue in Tink Java","details":"A mis-handling of invalid unicode characters in the Java implementation of Tink versions prior to 1.5 allows an attacker to change the ID part of a ciphertext, which result in the creation of a second ciphertext that can decrypt to the same plaintext. This can be a problem with encrypting deterministic AEAD with a single key, and rely on a unique ciphertext-per-plaintext.","published":"2020-10-19T13:15:13.437Z","modified":"2026-07-09T00:38:13.910797Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Maven","name":"com.google.crypto.tink:tink","fixedVersion":"1.5.0"}],"fix":{"url":"https://github.com/google/tink/commit/93d839a5865b9d950dffdc9d0bc99b71280a8899","label":"google/tink@93d839a"},"references":[{"type":"FIX","url":"https://github.com/google/tink/commit/93d839a5865b9d950dffdc9d0bc99b71280a8899"},{"type":"FIX","url":"https://github.com/google/tink/security/advisories/GHSA-g5vf-v6wf-7w2r"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T00:38:13.910797Z"}}