{"id":"CVE-2026-31253","aliases":["PYSEC-2026-2477"],"url":"https://o3.security/vulnerability/CVE-2026-31253","summary":"flash-attention contains an insecure deserialization vulnerability in its checkpoint loading mechanism","details":"The flash-attention training framework thru commit e724e2588cbe754beb97cf7c011b5e7e34119e62 (2025-13-04) contains an insecure deserialization vulnerability (CWE-502) in its checkpoint loading mechanism. The load_checkpoint() function in checkpoint.py and the checkpoint loading code in eval.py use torch.load() without enabling the security-restrictive weights_only=True parameter. This allows the deserialization of arbitrary Python objects via the pickle module. An attacker can exploit this by providing a maliciously crafted checkpoint file. When a victim loads this checkpoint during model warmstarting or evaluation, arbitrary code is executed on the victim's system.","published":"2026-05-11T18:31:44Z","modified":"2026-07-14T05:30:20.366472231Z","cvss":{"score":7.3,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"},"epss":{"score":0.00218,"percentile":0.12472,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"flash-attn","fixedVersion":null}],"fix":null,"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31253"},{"type":"PACKAGE","url":"https://github.com/Dao-AILab/flash-attention"},{"type":"WEB","url":"https://www.notion.so/CVE-2026-31253-35d1e1393188813f9e77e2038104bc49"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-14T05:30:20.366472231Z"}}