Cloudanix VulnDB

CVE-2026-53501

High · 8.2

CVSS

8.2

EPSS

0.4%

Published

Jul 31, 2026

CISA due date

—

The record

Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor’s HMAC validation can be bypassed due to the use of Python’s .replace() when removing the signature from the URL before validation. Since .replace() removes all occurrences of the substring, an attacker can insert the same signature multiple times in the URL and manipulate the final URL used for validation. This allows crafting URLs where the validated string differs from the actual requested resource, enabling loading images from unintended domains or paths. This issue is fixed in 7.8.0.

Affected packages

Ecosystem Package Introduced Fixed

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