CVE-2026-53503 Details
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.
A denial-of-service vulnerability has been identified in Thumbor, an open-source photo thumbnail service, in versions prior to 7.8.0. The issue arises in the convolution filter, where the user-controlled 'columns' value is passed to a C extension without proper validation. When 'columns' is set to zero, it triggers a divide-by-zero error, causing a crash in the Thumbor process. This vulnerability can be exploited remotely, leading to a process termination and a denial-of-service condition.
Users are advised to upgrade to Thumbor version 7.8.0 or later, where this vulnerability has been fixed. In version 7.8.0, the convolution filter has been updated to reject 'columns' values of zero, preventing the divide-by-zero error in the C extension.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jul 31, 2026CISA-ADP
Assessed Jul 31, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/thumbor/thumbor/security/advisories/GHSA-cqjp-jf4r-h5q9 | CISA-ADP | AdvisoryRemedyVendor |
| https://github.com/thumbor/thumbor/commit/447e192e3fb92e64c12e5354a56a4a7133f69d73 | [email protected] | Source CodeVendor |
| https://github.com/thumbor/thumbor/releases/tag/7.8.0 | [email protected] | Release NotesVendor |
| https://github.com/thumbor/thumbor/security/advisories/GHSA-cqjp-jf4r-h5q9 | [email protected] | AdvisoryRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-20 | Improper Input Validation | [email protected] |
| CWE-369 | Divide By Zero | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Thumbor | <= 7.7.7 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 31, 2026 | CVE Modified | CISA-ADP |
| Jul 31, 2026 | New CVE Received | [email protected] |