CVE-2026-62239

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.

CVSS 4.0

5.3CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

6.6CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

EPSS

0.2% chance of exploitation in the next 30 days; higher than 5% of CVEs (scores of 2026-10-25)

CWE

CWE-59

Published

2026-07-13

Modified

2026-10-24

Record from

the NVD, synced 2026-10-25

References

• https://github.com/Dao-AILab/flash-attention/commit/0816ef12f424c6ec94b057a72c275b14f6e6edb2
• https://github.com/Dao-AILab/flash-attention/issues/2637
• https://github.com/Dao-AILab/flash-attention/pull/2702
• https://www.vulncheck.com/advisories/flashattention-symlink-attack-via-tarfile-extractall-in-hopper-setup-py
• https://github.com/Dao-AILab/flash-attention/issues/2637

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