CVE-2026-53500

Thumbor treats ALLOWED_SOURCES string patterns as unescaped regex, allowing hostname bypass via wildcard dot

State: Published
Severity: 8.2 High
Published: Jul 31, 2026
Updated: Jul 31, 2026
Reserved: Jun 9, 2026

Description

Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, the ALLOWED_SOURCES configuration passes plain strings to re.match() without escaping dots, so a hostname differing at dot positions can match the allowlist. This issue is fixed in 7.8.0.

Scores

CVSS	Score	Vector	Source
3.1	8.2 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L	GitHub_M

Weaknesses

CWE-918 Server-Side Request Forgery (SSRF)

Affected Products

Product	Versions
thumborthumbor	< 7.8.0Affected

References

https://github.com/thumbor/thumbor/security/advisories/GHSA-6x26-6r6f-m537
https://github.com/thumbor/thumbor/commit/68876715350c6c8f49c324e5515e64908830aed7
https://github.com/thumbor/thumbor/releases/tag/7.8.0

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