PYSEC-2025-242

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:H/A:N

EPSS

• CVE-2025-46814: 0.34% estimated exploitation activity in the next 30 days; percentile 27.02 (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.

FastAPI Guard is a security library for FastAPI that provides middleware to control IPs, log requests, and detect penetration attempts. An HTTP header injection vulnerability has been identified in versions prior to 2.0.0. By manipulating the X-Forwarded-For header, an attacker can potentially inject arbitrary IP addresses into the request. This vulnerability can allow attackers to bypass IP-based access controls, mislead logging systems, and impersonate trusted clients. It is especially impactful when the application relies on the X-Forwarded-For header for IP-based authorization or authentication. Users should upgrade to FastAPI Guard version 2.0.0 to receive a fix.

Published by the source

6 May 2025, 15:16 UTC

Last modified by the source

13 Jul 2026, 07:15 UTC

Source last checked

24 Oct 2026, 04:13 UTC

1. Revision 1 · created · 24 Oct 2026

   Published from osv record PYSEC-2025-242

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2025-46814

Advisory: PYSEC-2025-242
IDs: CVE-2025-46814, GHSA-77q8-qmj7-x7pp
Record: https://patchnext.com/advisories/cve-2025-46814 (revision 1, source checked 24 Oct 2026, 04:13 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: fastapi-guard 2.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI fastapi-guard: affected < 2.0.0; fixed in 2.0.0

## Suggested inspection (read-only)
- `python -m pip show fastapi-guard`: 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 fastapi-guard.
- 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/PYSEC-2025-242 (OSV record PYSEC-2025-242 lists affected ranges: PyPI fastapi-guard >=0 <2.0.0 (fixed))

Commands are suggestions: review each one before running it.