What’s Vulnerable › Vulnerabilities

CVE-2026-25478: Litestar has a CORS origin allowlist bypass due to unescaped regex metacharacters in allowed origins

• 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-942

Description

Litestar is an Asynchronous Server Gateway Interface (ASGI) framework. Prior to 2.20.0, CORSConfig.allowed_origins_regex is constructed using a regex built from configured allowlist values and used with fullmatch() for validation. Because metacharacters are not escaped, a malicious origin can match unexpectedly. The check relies on allowed_origins_regex.fullmatch(origin). 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/eb87703b309efcc0d1b087dcb12784e76b003d5a
• https://github.com/litestar-org/litestar/releases/tag/v2.20.0
• https://github.com/litestar-org/litestar/security/advisories/GHSA-2p2x-hpg8-cqp2

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