CVE-2026-62239 PUBLISHED

FlashAttention Symlink Attack via tarfile.extractall in hopper/setup.py

Assigner: VulnCheck
Reserved: 13.07.2026 Published: 13.07.2026 Updated: 14.07.2026

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.

Metrics

CVSS Vector: CVSS: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 Score: 5.3

Product Status

Vendor Dao-AILab
Product flash-attention
Versions Default: unaffected
  • affected from 0 to 2.8.3.post1 (incl.)
  • Version 0816ef12f424c6ec94b057a72c275b14f6e6edb2 is unaffected

Credits

  • YU SUN finder

References

Problem Types

  • Improper Link Resolution Before File Access ('Link Following') CWE