Is CVE-2026-53502 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-53502 being exploited in the wild.

How severe is CVE-2026-53502?

Medium severity, with a CVSS score of 4, published 31 July 2026.

Which products and versions are affected?

thumbor (PyPI) ECOSYSTEM:introduced=0,fixed=7.8.0.

Is there a fix for CVE-2026-53502?

Yes. thumbor (PyPI): upgrade to 7.8.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-53502 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-53502?

Check whether you run thumbor (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-53502: Thumbor path traversal in file_loader via encoded path segments

CVE-2026-53502 · Severity: medium · CVSS 4 · Published 2026-07-31

Thumbor is an open-source service used to resize and process images on the fly. A security flaw in how it handles file paths allows an attacker to bypass security restrictions and access sensitive files on the server, such as configuration files or system secrets. This could lead to the exposure of private data or credentials used by the organization.

Technologies: thumbor (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2026-53502 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-53502 being exploited in the wild.
How severe is CVE-2026-53502?: Medium severity, with a CVSS score of 4, published 31 July 2026.
Which products and versions are affected?: thumbor (PyPI) ECOSYSTEM:introduced=0,fixed=7.8.0.
Is there a fix for CVE-2026-53502?: Yes. thumbor (PyPI): upgrade to 7.8.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-53502 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-53502?: Check whether you run thumbor (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

thumbor (PyPI): upgrade to 7.8.0 or later
```
pip install "thumbor>=7.8.0"
```

Technical details

A path traversal vulnerability exists in Thumbor's 'file_loader' component due to improper input validation order. The loader performs security checks (abspath and startswith) on the file path before applying URL decoding (unquote). An attacker can provide double-encoded or percent-encoded traversal sequences (e.g., %252e%252e) via the watermark or frame filters. These sequences bypass the initial directory boundary check as literal strings but are subsequently decoded into '..' sequences, allowing the attacker to read arbitrary files outside the intended root directory. This issue is resolved in version 7.8.0 by enforcing root boundaries after decoding.

Affected products

thumbor thumbor < 7.8.0

Identifiers

CVE-2026-53502
GHSA-cj54-hpcc-gj6h
PYSEC-2026-3618

Timeline

2026-05-30: patched: Version 7.8.0 released
2026-06-10: advisory: GitHub Security Advisory published
2026-07-31: disclosed: CVE published to NVD

References

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