{"id":"CVE-2026-53503","state":"PUBLISHED","title":"Thumbor convolution filter allows divide-by-zero in C extension leading to remote DoS","description":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:convolution(<matrix>, <columns>, <should_normalize>) filter passes the user-controlled <columns> value to a C extension (thumbor/ext/filters/_convolution.c) where it is used as a divisor (for % and /) without validating columns > 0. When columns=0, the C code triggers undefined behavior; on x86_64 this reliably results in a fatal divide-by-zero trap (SIGFPE) and crashes the Thumbor process, causing a remote denial of service. This issue is fixed in 7.8.0.","publishedAt":"2026-07-31T18:54:20.747Z","updatedAt":"2026-07-31T21:39:35.108Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["thumbor thumbor"],"affected":[{"vendor":"thumbor","product":"thumbor","versions":[{"version":"< 7.8.0","status":"affected"}]}],"references":["https://github.com/thumbor/thumbor/security/advisories/GHSA-cqjp-jf4r-h5q9","https://github.com/thumbor/thumbor/commit/447e192e3fb92e64c12e5354a56a4a7133f69d73","https://github.com/thumbor/thumbor/releases/tag/7.8.0"],"weaknesses":["CWE-20","CWE-369"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53503.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53503","state":"PUBLISHED","datePublished":"2026-07-31T18:54:20.747Z","dateUpdated":"2026-07-31T21:39:35.108Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-09T17:05:25.059Z"},"containers":{"cna":{"title":"Thumbor convolution filter allows divide-by-zero in C extension leading to remote DoS","descriptions":[{"lang":"en","value":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:convolution(<matrix>, <columns>, <should_normalize>) filter passes the user-controlled <columns> value to a C extension (thumbor/ext/filters/_convolution.c) where it is used as a divisor (for % and /) without validating columns > 0. When columns=0, the C code triggers undefined behavior; on x86_64 this reliably results in a fatal divide-by-zero trap (SIGFPE) and crashes the Thumbor process, causing a remote denial of service. This issue is fixed in 7.8.0."}],"affected":[{"vendor":"thumbor","product":"thumbor","versions":[{"version":"< 7.8.0","status":"affected"}]}],"references":[{"url":"https://github.com/thumbor/thumbor/security/advisories/GHSA-cqjp-jf4r-h5q9","name":"https://github.com/thumbor/thumbor/security/advisories/GHSA-cqjp-jf4r-h5q9","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/thumbor/thumbor/commit/447e192e3fb92e64c12e5354a56a4a7133f69d73","name":"https://github.com/thumbor/thumbor/commit/447e192e3fb92e64c12e5354a56a4a7133f69d73","tags":["x_refsource_MISC"]},{"url":"https://github.com/thumbor/thumbor/releases/tag/7.8.0","name":"https://github.com/thumbor/thumbor/releases/tag/7.8.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","lang":"en","description":"CWE-20: Improper Input Validation","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-369","lang":"en","description":"CWE-369: Divide By Zero","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-31T18:54:20.747Z"},"source":{"advisory":"GHSA-cqjp-jf4r-h5q9","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/thumbor/thumbor/security/advisories/GHSA-cqjp-jf4r-h5q9","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-31T20:14:06.472673Z","id":"CVE-2026-53503","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-31T21:39:35.108Z"}}]}}}