Vulnerability · Published Jul 31, 2026 · Assigned by GitHub_M
CVE-2026-53500Thumbor treats ALLOWED_SOURCES string patterns as unescaped regex, allowing hostname bypass via wildcard dot
High 8.2
In plain English
A high-severity server-side request forgery in thumbor from thumbor. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)8.2High
Exploit odds (30 days)0.5%top 57.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:14 | thumbor | 7.8.0-1 | DEBIAN-CVE-2026-53500 |
| PyPI | thumbor | 7.8.0 | GHSA-6x26-6r6f-m537 |
| PyPI | thumbor | 7.8.0 | PYSEC-2026-3617 |
| Ubuntu:26.04:LTS | thumbor | no fix listed | UBUNTU-CVE-2026-53500 |
Affected products (as reported)
Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L
References
- https://github.com/thumbor/thumbor/security/advisories/GHSA-6x26-6r6f-m537 x_refsource_CONFIRM
- https://github.com/thumbor/thumbor/commit/68876715350c6c8f49c324e5515e64908830aed7 x_refsource_MISC
- https://github.com/thumbor/thumbor/releases/tag/7.8.0 x_refsource_MISC