{"id":"CVE-2026-62239","aliases":["EUVD-2026-43554","GHSA-w9r7-4gwr-j959"],"status":"published","title":"FlashAttention Symlink Attack via tarfile.extractall in hopper/setup.py","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.","severity":{"version":"4.0","score":5.3,"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00164,"percentile":0.05672,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-59"],"published":"2026-07-13T21:03:32Z","modified":"2026-10-28T02:31:11Z","products":[{"vendor":"dao-ailab","product":"flash-attention"}],"references":[{"url":"https://github.com/Dao-AILab/flash-attention/issues/2637","tags":["technical-description","exploit","issue-tracking","report"]},{"url":"https://github.com/Dao-AILab/flash-attention/pull/2702","tags":["issue-tracking","patch","fix"]},{"url":"https://github.com/Dao-AILab/flash-attention/commit/0816ef12f424c6ec94b057a72c275b14f6e6edb2","tags":["patch","fix"]},{"url":"https://www.vulncheck.com/advisories/flashattention-symlink-attack-via-tarfile-extractall-in-hopper-setup-py","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-62239","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-w9r7-4gwr-j959"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62239.json","tags":["advisory"]},{"url":"https://github.com/Dao-AILab/flash-attention","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-62239","title":"FlashAttention Symlink Attack via tarfile.extractall in hopper/setup.py","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.","status":"published","published":"2026-07-13T21:03:32.262Z","modified":"2026-09-17T17:54:31.095Z","cvss":[{"version":"4.0","score":5.3,"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","level":"medium","assessor":"cna"},{"version":"3.1","score":6.6,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T14:20:14.999906Z"}],"euvd":[{"id":"EUVD-2026-43554","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.","status":"published","published":"2026-07-13T21:03:32Z","modified":"2026-09-17T17:54:31Z","cvss":[{"version":"4.0","score":5.3,"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","level":"medium"}],"updated_at":"2026-11-02T17:28:10.833571Z"}],"ghsa":[{"id":"GHSA-w9r7-4gwr-j959","title":"FlashAttention through 2.8.3.post1, fixed in commit 0816ef1, contains a symlink attack...","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.","status":"published","published":"2026-07-14T00:31:04Z","modified":"2026-07-14T00:31:11Z","cvss":[{"version":"4.0","score":5.3,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium"},{"version":"3.1","score":6.6,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N","level":"medium"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T15:09:26.474991Z"}],"nvd":[{"id":"CVE-2026-62239","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.","status":"published","published":"2026-07-13T22:16:51.967Z","modified":"2026-10-24T22:10:00.21Z","cvss":[{"version":"4.0","score":5.3,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.6,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T14:12:29.114188Z"}],"osv":[{"id":"CVE-2026-62239","title":"FlashAttention Symlink Attack via tarfile.extractall in hopper/setup.py","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.","status":"published","published":"2026-07-13T21:03:32.262Z","modified":"2026-10-28T02:31:11.998053418Z","cvss":[{"version":"4.0","score":5.3,"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","level":"medium"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T15:45:12.933503Z"}]}}