{"id":"CVE-2026-53501","title":"Thumbor is an open-source photo thumbnail service by globo.com","summary":"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() …","severity":"high","cvss":8.2,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","cwe":["CWE-347"],"vendor":"thumbor","product":"thumbor","affected":["thumbor <= 7.7.7"],"patched":["thumbor 7.8.0"],"published":"2026-07-31","updated":"2026-09-08","sourceUpdated":"2026-09-08T20:51:43.490","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53501","references":[{"url":"https://github.com/thumbor/thumbor/commit/e3ae3e2500537b4d735df4144129a649374bb70b","label":"security-advisories@github.com"},{"url":"https://github.com/thumbor/thumbor/releases/tag/7.8.0","label":"security-advisories@github.com"},{"url":"https://github.com/thumbor/thumbor/security/advisories/GHSA-mw3h-qjxj-6xg9","label":"security-advisories@github.com"},{"url":"https://github.com/advisories/GHSA-mw3h-qjxj-6xg9"}],"tags":["nvd","ghsa","pip"],"epss":0.00208,"epssPercentile":0.11245,"aliases":["GHSA-mw3h-qjxj-6xg9"],"ecosystem":"pip","ingestedAt":"2026-07-31T19:01:36.572Z","slug":"CVE-2026-53501","body":"## Overview\n\nThumbor 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-53501)\n\nAffected packages:\n\n- `thumbor <= 7.7.7`\n\nPatched in:\n\n- `thumbor 7.8.0`\n\nSource: https://github.com/advisories/GHSA-mw3h-qjxj-6xg9","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":45.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}