CVE-2026-25479: Litestar's AllowedHosts has a validation bypass due to unescaped regex metacharacters in configured host patterns

CVE-2026-25479 · Severity: low · CVSS 3.1 · Published 2026-02-09

Litestar is an Asynchronous Server Gateway Interface (ASGI) framework. Prior to 2.20.0, in litestar.middleware.allowed_hosts, allowlist entries are compiled into regex patterns in a way that allows regex metacharacters to retain special meaning (e.g., . matches any character). This enables a bypass where an attacker supplies a host that matches the regex but is not the intended literal hostname. This vulnerability is fixed in 2.20.0.

Technologies: litestar (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2026-25479 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-25479 being exploited in the wild.
How severe is CVE-2026-25479?
Low severity, with a CVSS score of 3.1, published 9 February 2026.
Which products and versions are affected?
litestar (PyPI) ECOSYSTEM:introduced=0,fixed=2.20.0, ECOSYSTEM:introduced=2.19.0,fixed=2.20.0.
Is there a fix for CVE-2026-25479?
Yes. litestar (PyPI): upgrade to 2.20.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-25479?
Check whether you run litestar (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

  • litestar (PyPI): upgrade to 2.20.0 or later
    pip install "litestar>=2.20.0"

Affected products

  • litestar (PyPI) ECOSYSTEM:introduced=0,fixed=2.20.0, ECOSYSTEM:introduced=2.19.0,fixed=2.20.0

Identifiers

  • CVE-2026-25479
  • GHSA-93ph-p7v4-hwh4
  • PYSEC-2026-2196

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