| Summary | UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Prior to 5.13.0, ujson.dumps() (or ujson.dump() or ujson.encode()) have a reject_bytes=False option. When set, they may accept malformed or truncated UTF-8 byte sequences, silently rewriting them into different Unicode characters instead of rejecting them. This leads to input validation bypass and data integrity issues. This vulnerability is fixed in 5.13.0. |
|---|---|
| Publication Date | June 23, 2026, 7:16 a.m. |
| Registration Date | June 27, 2026, 4:12 a.m. |
| Last Update | June 24, 2026, 12:50 a.m. |
| CVSS3.1 : MEDIUM | |
| スコア | 6.5 |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
| 攻撃元区分(AV) | ネットワーク |
| 攻撃条件の複雑さ(AC) | 低 |
| 攻撃に必要な特権レベル(PR) | 不要 |
| 利用者の関与(UI) | 不要 |
| 影響の想定範囲(S) | 変更なし |
| 機密性への影響(C) | 低 |
| 完全性への影響(I) | 低 |
| 可用性への影響(A) | なし |