Regex Misconfiguration in Thumbor Open-Source Photo Service
CVE-2026-53500

8.2HIGH

Key Information:

Vendor

Thumbor

Status
Thumbor
Vendor
CVE Published:
31 July 2026

What is CVE-2026-53500?

Thumbor, an open-source photo thumbnail service developed by Globo, contains a regex misconfiguration in its ALLOWED_SOURCES setting. Versions prior to 7.8.0 pass unescaped strings to the re.match() function, allowing for potential bypass of the hostname validation due to matching on incorrect dot positions. This vulnerability has been addressed in Thumbor version 7.8.0, ensuring that proper regex handling secures the hostname matching against unauthorized sources.

Affected Version(s)

thumbor < 7.8.0

References

https://github.com/thumbor/thumbor/security/advisories/GH...
x_refsource_CONFIRM
https://github.com/thumbor/thumbor/commit/68876715350c6c8...
x_refsource_MISC
https://github.com/thumbor/thumbor/releases/tag/7.8.0
x_refsource_MISC

CVSS V3.1

Score:
8.2
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.