p PatchFirst

CVE-2026-53501

CVE-2026-53501 · Thumbor has HMAC validation bypass via multiple .replace() calls when removing URL signature

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 8.2 · High · EPSS 0.4% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • thumbor

    Versions
    • < 7.8.0: Affected

    No fix published

  • thumbor Debian:14

    Versions
    • 6.3.2-3
    • 6.3.2-4
    • 6.5.1-1
    • 6.5.1-2
    • 6.5.1-3
    • 6.5.1-4
    • 6.5.1-5
    • 6.5.1-6
    • 6.5.1-7
    • 6.7.0-1
    • 7.7.7-1
    • 7.7.7-2
    • 7.7.7-3
    • 7.7.7-4
    • 7.7.7-5
    • 7.7.7-6
    Affected ranges
    • ECOSYSTEM: < 7.8.0-1

    Update to 7.8.0-1

  • thumbor PyPI

    Versions
    • 4.1.3
    • 4.10.0
    • 4.10.1
    • 4.10.2
    • 4.10.3
    • 4.11.0
    • 4.11.1
    • 4.12.0
    • 4.12.1
    • 4.12.2
    • 4.4.1
    • 4.5.3
    • 4.5.4
    • 4.6.0
    • 4.7.0
    • 4.7.1
    • 4.8.0
    • 4.8.1
    • 4.8.2
    • 4.8.3
    • 4.8.4
    • 4.8.5
    • 4.8.6
    • 4.9.0
    • 4.9.1
    • 5.0.0
    • 5.0.0rc1
    • 5.0.0rc2
    • 5.0.1
    • 5.0.2
    • 5.0.3
    • 5.0.4
    • 5.0.5
    • 5.0.6
    • 5.1.0
    • 5.2.0
    • 5.2.1
    • 6.0.0
    • 6.0.0b1
    • 6.0.0b2
    • 6.0.0b3
    • 6.0.0b4
    • 6.0.0b5
    • 6.0.1
    • 6.0.2
    • 6.1.0
    • 6.1.1
    • 6.1.2
    • 6.1.3
    • 6.1.4
    • 6.1.5
    • 6.2.0
    • 6.2.1
    • 6.3.0
    • 6.3.1
    • 6.3.2
    • 6.4.0
    • 6.4.1
    • 6.4.2
    • 6.4.3
    • 6.5.0
    • 6.5.1
    • 6.5.2
    • 6.6.0
    • 6.6.1
    • 6.7.0
    • 6.7.1
    • 6.7.2
    • 6.7.3
    • 6.7.4
    • 6.7.5
    • 6.7.6
    • 7.0.0
    • 7.0.0a1
    • 7.0.0a2
    • 7.0.0a3
    • 7.0.0a4
    • 7.0.0a5
    • 7.0.0b1
    • 7.0.1
    • 7.0.10
    • 7.0.11
    • 7.0.12
    • 7.0.2
    • 7.0.3
    • 7.0.5
    • 7.0.6
    • 7.0.7
    • 7.0.8
    • 7.0.9
    • 7.1.0
    • 7.1.1
    • 7.1.2
    • 7.2.0
    • 7.2.1
    • 7.3.0
    • 7.3.1
    • 7.3.2
    • 7.4.0
    • 7.4.1
    • 7.4.2
    • 7.4.3
    • 7.4.4
    • 7.4.5
    • 7.4.6
    • 7.4.7
    • 7.5.0
    • 7.5.1
    • 7.5.2
    • 7.6.0
    • 7.7.0
    • 7.7.1
    • 7.7.2
    • 7.7.3
    • 7.7.4
    • 7.7.5
    • 7.7.6
    • 7.7.7
    Affected ranges
    • ECOSYSTEM: < 7.8.0

    Update to 7.8.0

  • thumbor Ubuntu:26.04:LTS

    Versions
    • 7.7.7-4
    • 7.7.7-5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

Check your server →