PT-2026-57903 · Dao Ailab · Flash-Attention

Yu Sun · Published 2026-07-13 · Updated 2026-07-13 · CVE-2026-62239

Mitre

CVSS v3.1

6.6

Medium

Base vector

AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

FlashAttention through 2.8.3.post1, fixed in commit 0816ef1, contains a symlink attack vulnerability in the download and copy() function within hopper/setup.py that extracts NVIDIA toolchain archives without validating symlinks or filtering tar members. A local attacker can pre-plant a symlink in the predictable cache directory to redirect extracted binaries to an attacker-chosen location, enabling arbitrary file write with victim privileges during build time.

Exploit

Fix

Link Following

Weakness Enumeration

CWE-59

Related Identifiers

CVE-2026-62239

Affected Products

Flash-Attention

References · 5

• 🔥 https://github.com/Dao-AILab/flash-attention/issues/2637 · Exploit
• https://github.com/Dao-AILab/flash-attention/commit/0816ef12f424c6ec94b057a72c275b14f6e6edb2 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-62239 · Security Note
• https://github.com/Dao-AILab/flash-attention/pull/2702 · Note
• https://vulncheck.com/advisories/flashattention-symlink-attack-via-tarfile-extractall-in-hopper-setup-py · Note