{"cve":"CVE-2026-53501","nvd":{"published":"2026-07-31T19:17:09.413","modified":"2026-09-08T20:51:43.490","status":"Deferred","description":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor’s HMAC validation can be bypassed due to the use of Python’s .replace() when removing the signature from the URL before validation. Since .replace() removes all occurrences of the substring, an attacker can insert the same signature multiple times in the URL and manipulate the final URL used for validation. This allows crafting URLs where the validated string differs from the actual requested resource, enabling loading images from unintended domains or paths. This issue is fixed in 7.8.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","score":8.2},"cwes":["CWE-347"],"references":["https://github.com/thumbor/thumbor/commit/e3ae3e2500537b4d735df4144129a649374bb70b","https://github.com/thumbor/thumbor/releases/tag/7.8.0","https://github.com/thumbor/thumbor/security/advisories/GHSA-mw3h-qjxj-6xg9"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:47:10.050265369+00:00"},"epss":{"cve":"CVE-2026-53501","score":0.00352,"percentile":0.28897,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-mw3h-qjxj-6xg9","url":"https://osv.dev/vulnerability/GHSA-mw3h-qjxj-6xg9","summary":"Thumbor has HMAC validation bypass via multiple .replace() calls when removing URL signature","modified":"2026-08-04T14:40:46.956077457Z","packages":[{"ecosystem":"PyPI","name":"thumbor","purl":"pkg:pypi/thumbor","ranges":["<7.8.0"],"fixed":["7.8.0"]}]},{"id":"PYSEC-2026-3620","url":"https://osv.dev/vulnerability/PYSEC-2026-3620","summary":"Thumbor has HMAC validation bypass via multiple .replace() calls when removing URL signature","modified":"2026-08-04T14:30:16.418003073Z","packages":[{"ecosystem":"PyPI","name":"thumbor","purl":"pkg:pypi/thumbor","ranges":["<7.8.0"],"fixed":["7.8.0"]}]}],"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."]}