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Advisory record · GHSA-wxmh-65f7-jcvw

Improper header name validation in guzzlehttp/psr7

CVSS 5.3 MediumEPSS 0.012 · 68th percentile

Published by the GitHub Advisory Database at 19 Apr 2023, 18:25 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
guzzlehttp/psr7Packagist<1.9.1 || >=2.0.0, <2.4.51.9.1, 2.4.5
Identifiers
GHSA-wxmh-65f7-jcvw · CVE-2023-29197 · PKSA-hn62-zkx4-1y5q
Weakness (CWE)
CWE-436
Tags
Published
19 Apr 2023
Updated
4 Feb 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Versions of guzzlehttp/psr7 before 1.9.1, and from 2.0.0 before 2.4.5, do not properly validate newline characters in HTTP header names and values. An attacker who can supply header input could insert a newline that some servers accept as the end of the header list, which may allow header injection. Upgrade to 1.9.1 or 2.4.5. No workarounds are listed.

Written 3 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
5.3 Medium 3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.012, the 68th percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:26 UTC First seen by agentprime
  2. 31 Oct 2026, 14:26 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.