{"id":"GHSA-r38m-44fw-h886","summary":"AEADs/ascon-aead: Plaintext exposed in decrypt_in_place_detached even on tag verification failure","details":"### Summary\nIn `decrypt_in_place_detached`, the decrypted ciphertext (which is the correct ciphertext) is exposed even if the tag is incorrect.\n\n### Details\nThis is because in [decrypt_inplace](https://github.com/RustCrypto/AEADs/blob/8cda109f1128c4c7953a0bb0f53e1056d537e462/ascon-aead/src/asconcore.rs#L350-L364) in asconcore.rs, tag verification causes an error to be returned with the plaintext contents still in `buffer`. The root cause of this vulnerability is similar to https://github.com/RustCrypto/AEADs/security/advisories/GHSA-423w-p2w9-r7vq\n\n### PoC\n```rust\nuse ascon_aead::Tag;\nuse ascon_aead::{Ascon128, Key, Nonce};\nuse ascon_aead::aead::{AeadInPlace, KeyInit};\n\nfn main() {\n\n    let key = Key::\u003cAscon128\u003e::from_slice(b\"very secret key.\");\n    let cipher = Ascon128::new(key);\n\n    let nonce = Nonce::\u003cAscon128\u003e::from_slice(b\"unique nonce 012\"); // 128-bits; unique per message\n\n    let mut buffer: Vec\u003cu8\u003e = Vec::new(); // Buffer needs 16-bytes overhead for authentication tag\n    buffer.extend_from_slice(b\"plaintext message\");\n\n    // Encrypt `buffer` in-place detached, replacing the plaintext contents with ciphertext\n    cipher.encrypt_in_place_detached(nonce, b\"\", &mut buffer).expect(\"encryption failure!\");\n    \n    // Decrypt `buffer` in-place with the wrong tag, ignoring the decryption error\n    let _ = cipher.decrypt_in_place_detached(nonce, b\"\", &mut buffer, Tag::\u003cAscon128\u003e::from_slice(b\"\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\"));\n\n    assert_eq!(&buffer, b\"plaintext message\");\n}\n```\n### Impact\nIf a program continues to use the result of `decrypt_in_place_detached` after a decryption failure, the result will be unauthenticated. This may permit some forms of chosen ciphertext attacks (CCAs).","aliases":["CVE-2025-27498"],"modified":"2025-03-03T20:42:06.139683Z","published":"2025-03-03T20:22:19Z","database_specific":{"nvd_published_at":"2025-03-03T17:15:16Z","github_reviewed_at":"2025-03-03T20:22:19Z","severity":"MODERATE","github_reviewed":true,"cwe_ids":["CWE-347"]},"references":[{"type":"WEB","url":"https://github.com/RustCrypto/AEADs/security/advisories/GHSA-r38m-44fw-h886"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-27498"},{"type":"WEB","url":"https://github.com/RustCrypto/AEADs/commit/d1d749ba57e38e65b0e037cd744d0b17f7254037"},{"type":"PACKAGE","url":"https://github.com/RustCrypto/AEADs"}],"affected":[{"package":{"name":"ascon_aead","ecosystem":"crates.io","purl":"pkg:cargo/ascon_aead"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.4.3"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 0.4.2","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/03/GHSA-r38m-44fw-h886/GHSA-r38m-44fw-h886.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:A/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N"}]}