Litestar X-Forwarded-For Header Spoofing Vulnerability Enables Rate Limit Evasion

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2025-59152: 0.48% estimated exploitation activity in the next 30 days; percentile 41.81 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

While testing Litestar's RateLimitMiddleware, I discovered that rate limits can be completely bypassed by manipulating the X-Forwarded-For header. This renders IP-based rate limiting ineffective against determined attackers. The Problem Litestar's RateLimitMiddleware uses cachekeyfromrequest() 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. Looking at the relevant code in litestar/middleware/ratelimit.py around line 127, there's no validation of proxy headers or configuration for trusted proxies. Reproduction Steps Here's a minimal test case Testing the bypass Security Impact This vulnerability has several concerning implications: Brute…

Published by the source

6 Oct 2025, 20:18 UTC

Last modified by the source

7 Jul 2026, 17:56 UTC

Source last checked

26 Oct 2026, 13:35 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-hm36-ffrh-c77c

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-hm36-ffrh-c77c

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# Patch Next advisory brief: CVE-2025-59152

Advisory: Litestar X-Forwarded-For Header Spoofing Vulnerability Enables Rate Limit Evasion
IDs: CVE-2025-59152, GHSA-hm36-ffrh-c77c
Record: https://patchnext.com/advisories/cve-2025-59152 (revision 2, source checked 26 Oct 2026, 13:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: litestar 2.18.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI litestar: affected >= 2.17.0, <= 2.17.0; fixed in 2.18.0

## Suggested inspection (read-only)
- `python -m pip show litestar`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on litestar.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-hm36-ffrh-c77c (OSV record GHSA-hm36-ffrh-c77c lists affected ranges: PyPI litestar >=2.17.0 <2.18.0 (fixed))
- Verified: https://github.com/advisories/GHSA-hm36-ffrh-c77c (GitHub-reviewed advisory GHSA-hm36-ffrh-c77c lists affected ranges: PyPI litestar >=2.17.0 <=2.17.0)

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