What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-02-09 · updated 2026-06-17
• Weakness: CWE-185

Description

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.

Affected products

• litestar-org litestar: before 2.20.0 — fixed in 2.20.0

How to fix

Upgrade to a fixed version: litestar-org litestar 2.20.0. Check the vendor advisory for mitigations.

References

• https://docs.litestar.dev/2/release-notes/changelog.html#2.20.0
• https://github.com/litestar-org/litestar/commit/06b36f481d1bfea6f19995cfb4f203aba45c4ace
• https://github.com/litestar-org/litestar/releases/tag/v2.20.0
• https://github.com/litestar-org/litestar/security/advisories/GHSA-93ph-p7v4-hwh4

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