Vulnerability · Published Jul 31, 2026 · Assigned by GitHub_M

CVE-2026-53505Thumbor proportion filter allows unbounded post-transform resize leading to remote DoS

High 7.5

In plain English

A high-severity uncontrolled resource consumption in thumbor from thumbor. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.6%top 50.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:proportion(<value>) filter does not enforce an upper bound on <value> and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service. This issue is fixed in 7.8.0.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:14	thumbor	7.8.0-1	DEBIAN-CVE-2026-53505
PyPI	thumbor	7.8.0	GHSA-phj3-59pf-cp83
PyPI	thumbor	7.8.0	PYSEC-2026-3621
Ubuntu:26.04:LTS	thumbor	no fix listed	UBUNTU-CVE-2026-53505

Affected products (as reported)

Vendor	Product	Versions
thumbor	thumbor	< 7.8.0

Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/thumbor/thumbor/security/advisories/GHSA-phj3-59pf-cp83 x_refsource_CONFIRM
https://github.com/thumbor/thumbor/commit/2c716119de986cfc68c7071af52a98187e006023 x_refsource_MISC
https://github.com/thumbor/thumbor/releases/tag/7.8.0 x_refsource_MISC