{"id":"UBUNTU-CVE-2026-53503","details":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:convolution(\u003cmatrix\u003e, \u003ccolumns\u003e, \u003cshould_normalize\u003e) filter passes the user-controlled \u003ccolumns\u003e value to a C extension (thumbor/ext/filters/_convolution.c) where it is used as a divisor (for % and /) without validating columns \u003e 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.","modified":"2026-08-06T00:20:53Z","published":"2026-07-31T19:17:00Z","upstream":["CVE-2026-53503"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-53503"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-53503"},{"type":"REPORT","url":"https://github.com/thumbor/thumbor/security/advisories/GHSA-cqjp-jf4r-h5q9"},{"type":"REPORT","url":"https://github.com/thumbor/thumbor/commit/447e192e3fb92e64c12e5354a56a4a7133f69d73"},{"type":"REPORT","url":"https://github.com/thumbor/thumbor/releases/tag/7.8.0"}],"affected":[{"package":{"name":"thumbor","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/thumbor?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["7.7.7-4","7.7.7-5"],"ecosystem_specific":{"binaries":[{"binary_name":"thumbor","binary_version":"7.7.7-5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53503.json"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}