Vulnerability · Published Feb 9, 2026 · Assigned by GitHub_M

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

Medium 6.5

In plain English

A medium-severity security flaw in litestar from litestar-org. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 29% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.4%top 70.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	litestar	2.20.0	GHSA-93ph-p7v4-hwh4
PyPI	litestar	2.20.0	PYSEC-2026-2196

Affected products (as reported)

Vendor	Product	Versions
litestar-org	litestar	< 2.20.0

Weakness: CWE-185 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

References

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