cvedb.io
CVE-2026-53501
HIGH · CVSS 8.2
EPSS exploitation probability: 0%
Published 2026-07-31T19:17:09.413 · Last modified 2026-07-31T19:17:09.413

Summary

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.

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.