{"cve":"CVE-2025-53539","nvd":{"published":"2025-07-07T20:15:28.027","modified":"2026-06-17T09:38:24.673","status":"Analyzed","description":"FastAPI Guard is a security library for FastAPI that provides middleware to control IPs, log requests, and detect penetration attempts. fastapi-guard's penetration attempts detection uses regex to scan incoming requests. However, some of the regex patterns used in detection are extremely inefficient and can cause polynomial complexity backtracks when handling specially crafted inputs. This vulnerability is fixed in 3.0.1.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","score":6.9},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-1333"],"references":["https://github.com/rennf93/fastapi-guard/commit/d9d50e8130b7b434cdc1b001b8cfd03a06729f7f","https://github.com/rennf93/fastapi-guard/security/advisories/GHSA-j47q-rc62-w448"],"products":["fastapi-guard:fastapi_guard"],"source":"nvd","synced_at":"2026-10-19T22:04:28.436527499+00:00"},"epss":{"cve":"CVE-2025-53539","score":0.00481,"percentile":0.41541,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-j47q-rc62-w448","url":"https://osv.dev/vulnerability/GHSA-j47q-rc62-w448","summary":"fastapi-guard is vulnerable to ReDoS through inefficient regex","modified":"2026-07-07T17:56:52.023285837Z","packages":[{"ecosystem":"PyPI","name":"fastapi-guard","purl":"pkg:pypi/fastapi-guard","ranges":["<3.0.1"],"fixed":["3.0.1"]}]},{"id":"PYSEC-2026-1359","url":"https://osv.dev/vulnerability/PYSEC-2026-1359","summary":"fastapi-guard is vulnerable to ReDoS through inefficient regex","modified":"2026-07-07T17:47:35.930780691Z","packages":[{"ecosystem":"PyPI","name":"fastapi-guard","purl":"pkg:pypi/fastapi-guard","ranges":["<3.0.1"],"fixed":["3.0.1"]}]}],"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."]}