{"cve":"CVE-2026-49114","nvd":{"published":"2026-08-21T16:17:17.863","modified":"2026-10-15T19:10:00.173","status":"Analyzed","description":"In ONNX before 1.21.0, the 'save_external_data' function builds the external-data file path from the model's external_data location field and opens it for writing without 'O_NOFOLLOW/O_EXCL', after a non-atomic 'os.path.isfile()' check. A local attacker with write access to the directory where a victim serializes external data can deterministically pre-plant a symlink that is being followed, causing the victim's write to append to any file the victim can write, e.g. ~/.ssh/authorized_keys, cron files, or application configs. Fixed in 1.21.0.","cvss_v4":{"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N","score":6.8},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","score":7.1},"cwes":["CWE-22","CWE-59","CWE-367"],"references":["https://github.com/onnx/onnx/security/advisories/GHSA-q56x-g2fj-4rj6","https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-233-01.json","https://www.cve.org/CVERecord?id=CVE-2026-49114"],"products":["linuxfoundation:onnx"],"source":"nvd","synced_at":"2026-10-19T22:49:38.260478770+00:00"},"epss":{"cve":"CVE-2026-49114","score":0.00159,"percentile":0.05036,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-q56x-g2fj-4rj6","url":"https://osv.dev/vulnerability/GHSA-q56x-g2fj-4rj6","summary":"ONNX: TOCTOU arbitrary file read/write in save_external_dat ","modified":"2026-09-10T12:25:40.425961335Z","packages":[{"ecosystem":"PyPI","name":"onnx","purl":"pkg:pypi/onnx","ranges":["<1.21.0"],"fixed":["1.21.0"]}]},{"id":"PYSEC-2026-3876","url":"https://osv.dev/vulnerability/PYSEC-2026-3876","summary":"ONNX: TOCTOU arbitrary file read/write in save_external_dat ","modified":"2026-09-10T12:15:09.122031495Z","packages":[{"ecosystem":"PyPI","name":"onnx","purl":"pkg:pypi/onnx","ranges":["<1.21.0"],"fixed":["1.21.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}