CVE-2026-62239

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

MEDIUM
6.6
CVSS Score
Published: July 13, 2026 at 09:03 PM UTC
Updated: October 24, 2026 at 10:10 PM UTC
1 product affected across 1 vendorFlashAttention

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Severity
MEDIUM6.6
Exploit prediction
EPSS 0.2%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0 ≤ v ≤ 2.8.3.post10
Vendor states this is fixed in 0816ef12f424c6ec94b057a72c275b14f6e6edb2 (unaffected)
Vendor states this is fixed in 816ef12f424c6ec94b57a72c275b14f6e6edb2 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.6MEDIUMVulnCheck
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-59

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