Improper Input Validation Affecting thumbor package, versions <7.8.0-1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-THUMBOR-18492962
- published1 Aug 2026
- disclosed31 Jul 2026
Introduced: 31 Jul 2026
CVE-2026-53503 (opens in a new tab)How to fix?
Upgrade Debian:unstable thumbor to version 7.8.0-1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream thumbor package and not the thumbor package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
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.