{"id":"CVE-2025-6921","aliases":["EUVD-2025-30889","GHSA-4w7r-h757-3r74","PYSEC-2026-1980","openSUSE-SU-2026:11499-1"],"status":"published","title":"Regular Expression Denial of Service (ReDoS) in huggingface/transformers","description":"The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.","severity":{"version":"3.0","score":5.3,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00511,"percentile":0.44033,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-400"],"published":"2025-09-23T13:56:15Z","modified":"2026-10-28T02:30:25Z","fixes":[{"ecosystem":"PyPI","package":"transformers","fixed_in":["4.53.0"],"sources":["ghsa","osv"]},{"ecosystem":"openSUSE:Tumbleweed","package":"python-transformers","fixed_in":["5.15.0-1.1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"transformers","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.53.0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"transformers","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.53.0"}]}],"versions":["0.1","2.0.0","2.1.0","2.1.1","2.10.0","2.11.0","2.2.0","2.2.1","2.2.2","2.3.0","2.4.0","2.4.1","2.5.0","2.5.1","2.6.0","2.7.0","2.8.0","2.9.0","2.9.1","3.0.0","3.0.1","3.0.2","3.1.0","3.2.0","3.3.0","3.3.1","3.4.0","3.5.0","3.5.1","4.0.0","4.0.0rc1","4.0.1","4.1.0","4.1.1","4.10.0","4.10.1","4.10.2","4.10.3","4.11.0","4.11.1","4.11.2","4.11.3","4.12.0","4.12.1","4.12.2","4.12.3","4.12.4","4.12.5","4.13.0","4.14.0","4.14.1","4.15.0","4.16.0","4.16.1","4.16.2","4.17.0","4.18.0","4.19.0","4.19.1","4.19.2","4.19.3","4.19.4","4.2.0","4.2.1","4.2.2","4.20.0","4.20.1","4.21.0","4.21.1","4.21.2","4.21.3","4.22.0","4.22.1","4.22.2","4.23.0","4.23.1","4.24.0","4.25.0","4.25.1","4.26.0","4.26.1","4.27.0","4.27.1","4.27.2","4.27.3","4.27.4","4.28.0","4.28.1","4.29.0","4.29.1","4.29.2","4.3.0","4.3.0rc1","4.3.1","4.3.2","4.3.3","4.30.0","4.30.1","4.30.2","4.31.0","4.32.0","4.32.1","4.33.0","4.33.1","4.33.2","4.33.3","4.34.0","4.34.1","4.35.0","4.35.1","4.35.2","4.36.0","4.36.1","4.36.2","4.37.0","4.37.1","4.37.2","4.38.0","4.38.1","4.38.2","4.39.0","4.39.1","4.39.2","4.39.3","4.4.0","4.4.1","4.4.2","4.40.0","4.40.1","4.40.2","4.41.0","4.41.1","4.41.2","4.42.0","4.42.1","4.42.2","4.42.3","4.42.4","4.43.0","4.43.1","4.43.2","4.43.3","4.43.4","4.44.0","4.44.1","4.44.2","4.45.0","4.45.1","4.45.2","4.46.0","4.46.1","4.46.2","4.46.3","4.47.0","4.47.1","4.48.0","4.48.1","4.48.2","4.48.3","4.49.0","4.5.0","4.5.1","4.50.0","4.50.1","4.50.2","4.50.3","4.51.0","4.51.1","4.51.2","4.51.3","4.52.0","4.52.1","4.52.2","4.52.3","4.52.4","4.6.0","4.6.1","4.7.0","4.8.0","4.8.1","4.8.2","4.9.0","4.9.1","4.9.2"]},{"source":"osv","ecosystem":"PyPI","package":"transformers","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.53.0"}]}],"versions":["0.1","2.0.0","2.1.0","2.1.1","2.10.0","2.11.0","2.2.0","2.2.1","2.2.2","2.3.0","2.4.0","2.4.1","2.5.0","2.5.1","2.6.0","2.7.0","2.8.0","2.9.0","2.9.1","3.0.0","3.0.1","3.0.2","3.1.0","3.2.0","3.3.0","3.3.1","3.4.0","3.5.0","3.5.1","4.0.0","4.0.0rc1","4.0.1","4.1.0","4.1.1","4.10.0","4.10.1","4.10.2","4.10.3","4.11.0","4.11.1","4.11.2","4.11.3","4.12.0","4.12.1","4.12.2","4.12.3","4.12.4","4.12.5","4.13.0","4.14.0","4.14.1","4.15.0","4.16.0","4.16.1","4.16.2","4.17.0","4.18.0","4.19.0","4.19.1","4.19.2","4.19.3","4.19.4","4.2.0","4.2.1","4.2.2","4.20.0","4.20.1","4.21.0","4.21.1","4.21.2","4.21.3","4.22.0","4.22.1","4.22.2","4.23.0","4.23.1","4.24.0","4.25.0","4.25.1","4.26.0","4.26.1","4.27.0","4.27.1","4.27.2","4.27.3","4.27.4","4.28.0","4.28.1","4.29.0","4.29.1","4.29.2","4.3.0","4.3.0rc1","4.3.1","4.3.2","4.3.3","4.30.0","4.30.1","4.30.2","4.31.0","4.32.0","4.32.1","4.33.0","4.33.1","4.33.2","4.33.3","4.34.0","4.34.1","4.35.0","4.35.1","4.35.2","4.36.0","4.36.1","4.36.2","4.37.0","4.37.1","4.37.2","4.38.0","4.38.1","4.38.2","4.39.0","4.39.1","4.39.2","4.39.3","4.4.0","4.4.1","4.4.2","4.40.0","4.40.1","4.40.2","4.41.0","4.41.1","4.41.2","4.42.0","4.42.1","4.42.2","4.42.3","4.42.4","4.43.0","4.43.1","4.43.2","4.43.3","4.43.4","4.44.0","4.44.1","4.44.2","4.45.0","4.45.1","4.45.2","4.46.0","4.46.1","4.46.2","4.46.3","4.47.0","4.47.1","4.48.0","4.48.1","4.48.2","4.48.3","4.49.0","4.5.0","4.5.1","4.50.0","4.50.1","4.50.2","4.50.3","4.51.0","4.51.1","4.51.2","4.51.3","4.52.0","4.52.1","4.52.2","4.52.3","4.52.4","4.6.0","4.6.1","4.7.0","4.8.0","4.8.1","4.8.2","4.9.0","4.9.1","4.9.2"]},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"python-transformers","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.15.0-1.1"}]}]}],"products":[{"vendor":"huggingface","product":"huggingface/transformers"},{"vendor":"huggingface","product":"transformers"}],"references":[{"url":"https://huntr.com/bounties/287d15a7-6e7c-45d2-8c05-11e305776f1f","tags":["Exploit","Third Party Advisory","web"]},{"url":"https://github.com/huggingface/transformers/commit/47c34fba5c303576560cb29767efb452ff12b8be","tags":["Patch","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-6921","tags":["advisory"]},{"url":"https://github.com/huggingface/transformers/commit/d37f7517972f67e3f2194c000ed0f87f064e5099","tags":["web"]},{"url":"https://github.com/advisories/GHSA-4w7r-h757-3r74","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/6xxx/CVE-2025-6921.json","tags":["advisory"]},{"url":"https://github.com/huggingface/transformers","tags":["package"]},{"url":"https://pypi.org/project/transformers","tags":["package"]},{"url":"","tags":["advisory"]},{"url":"https://www.suse.com/security/cve/CVE-2025-6921","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2025-6921","title":"Regular Expression Denial of Service (ReDoS) in huggingface/transformers","description":"The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.","status":"published","published":"2025-09-23T13:56:15.636Z","modified":"2025-09-23T14:56:29.038Z","cvss":[{"version":"3.0","score":5.3,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:32:40.419293Z"}],"euvd":[{"id":"EUVD-2025-30889","description":"The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.","status":"published","published":"2025-09-23T13:56:15Z","modified":"2025-09-23T14:56:29Z","cvss":[{"version":"3.0","score":5.3,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T20:31:40.470019Z"}],"ghsa":[{"id":"GHSA-4w7r-h757-3r74","title":"Hugging Face Transformers vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer","description":"The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.","status":"published","published":"2025-09-23T15:31:09Z","modified":"2025-09-23T17:37:49Z","cvss":[{"version":"3.0","score":5.3,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:38:58.965005Z"}],"nvd":[{"id":"CVE-2025-6921","description":"The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.","status":"published","published":"2025-09-23T14:15:41.387Z","modified":"2026-10-11T20:10:00.2Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"3.0","score":5.3,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:11:32.559087Z"}],"osv":[{"id":"CVE-2025-6921","title":"Regular Expression Denial of Service (ReDoS) in huggingface/transformers","description":"The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.","status":"published","published":"2025-09-23T13:56:15.636Z","modified":"2026-10-28T02:30:25.931791389Z","cvss":[{"version":"3.0","score":5.3,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T15:44:52.859856Z"},{"id":"GHSA-4w7r-h757-3r74","title":"Hugging Face Transformers vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer","description":"The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.","status":"published","published":"2025-09-23T15:31:09Z","modified":"2026-09-10T03:50:27.867584538Z","cvss":[{"version":"3.0","score":5.3,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T15:46:37.528068Z"},{"id":"PYSEC-2026-1980","title":"Hugging Face Transformers vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer","description":"The huggingface/transformers library, versions prior to 4.53.0, is vulnerable to Regular Expression Denial of Service (ReDoS) in the AdamWeightDecay optimizer. The vulnerability arises from the _do_use_weight_decay method, which processes user-controlled regular expressions in the include_in_weight_decay and exclude_from_weight_decay lists. Malicious regular expressions can cause catastrophic backtracking during the re.search call, leading to 100% CPU utilization and a denial of service. This issue can be exploited by attackers who can control the patterns in these lists, potentially causing the machine learning task to hang and rendering services unresponsive.","status":"published","published":"2026-07-07T16:03:05.256373Z","modified":"2026-07-07T17:48:13.614617956Z","cvss":[{"version":"3.0","score":5.3,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:52:55.537808Z"},{"id":"openSUSE-SU-2026:11499-1","title":"python313-transformers-5.15.0-1.1 on GA media","description":"These are all security issues fixed in the python313-transformers-5.15.0-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2026-08-11T00:00:00Z","modified":"2026-08-12T10:45:07.665040014Z","updated_at":"2026-11-02T16:58:39.516824Z"}]}}