Vulnerability · Published Jul 31, 2026 · Assigned by GitHub_M
CVE-2026-53502Thumbor has path traversal via post-validation URL decoding bypass in file_loader
High 8.7
In plain English
A high-severity path traversal 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 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)8.7High
Exploit odds (30 days)0.5%top 55.5% 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, file_loader decodes percent-encoded path segments after its root-boundary validation, allowing traversal outside FILE_LOADER_ROOT_PATH through watermark or frame filter input. 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-2026-53502 |
| PyPI | thumbor | 7.8.0 | GHSA-cj54-hpcc-gj6h |
| PyPI | thumbor | 7.8.0 | PYSEC-2026-3618 |
| Ubuntu:26.04:LTS | thumbor | no fix listed | UBUNTU-CVE-2026-53502 |
Affected products (as reported)
Weakness: CWE-22 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
References
- https://github.com/thumbor/thumbor/security/advisories/GHSA-cj54-hpcc-gj6h x_refsource_CONFIRM
- https://github.com/thumbor/thumbor/commit/3b986d13677b30fe6651c8c72ebb25957ac0a40d x_refsource_MISC
- https://github.com/thumbor/thumbor/releases/tag/7.8.0 x_refsource_MISC