CVE-2026-53505

HIGH 7.5

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

CVSS Score

7.5

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-400
Vendor	thumbor
Product	thumbor
Published	Jul 31, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

thumbor / thumbor

< 7.8.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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