6.6Medium
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.
What this means for your business
- An attacker can use it only with access to the machine itself, with an ordinary user login, but only after tricking someone into an action such as opening a file or a link.
- FIRST's prediction model gives it a 0.2% chance of attack attempts being seen in the next 30 days, ranking above 5% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
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Scoring
- CVSS
- 6.6 (v3.1)
- Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N- CVSS v4
- 5.3
- Weakness
- CWE-59
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-07-13
- Last modified
- 2026-09-17
- Sources
- NVD
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