What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-31 · updated 2026-09-08
• Weakness: CWE-400

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 products

• thumbor: before 7.8.0

References

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

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