How severe is GHSA-wxmh-65f7-jcvw?

GHSA-wxmh-65f7-jcvw has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-wxmh-65f7-jcvw?

GHSA-wxmh-65f7-jcvw affects the following packages: guzzlehttp/psr7 (Packagist), guzzlehttp/psr7 (Packagist). Ecosystems affected: Packagist.

How do I fix GHSA-wxmh-65f7-jcvw?

Update guzzlehttp/psr7 to 1.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wxmh-65f7-jcvw is resolved across your whole dependency graph.

How do I detect GHSA-wxmh-65f7-jcvw in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for guzzlehttp/psr7, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-wxmh-65f7-jcvw if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is GHSA-wxmh-65f7-jcvw actively exploited in the wild?

Yes. There are 1 known exploit references for GHSA-wxmh-65f7-jcvw, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for GHSA-wxmh-65f7-jcvw?

GHSA-wxmh-65f7-jcvw has an EPSS (Exploit Prediction Scoring System) score of 1.2%, placing it in the 69th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-wxmh-65f7-jcvw?

GHSA-wxmh-65f7-jcvw is classified as CWE-436 (CWE-436). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-wxmh-65f7-jcvw published, and has it been updated?

GHSA-wxmh-65f7-jcvw was published on April 19, 2023 and was last updated on February 4, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

MEDIUM severity

Improper header name validation in guzzlehttp/psr7GHSA-wxmh-65f7-jcvw

MEDIUM

GHSA-wxmh-65f7-jcvw is a medium-severity (CVSS 5.3) CWE-436 vulnerability in guzzlehttp/psr7. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for guzzlehttp/psr7 — see the affected versions and patch details below.

Also known asCVE-2023-29197

Published

Apr 19, 2023

Updated

Feb 4, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

1 known

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs69th percentile — riskier than 69% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

🐘guzzlehttp/psr7🐘guzzlehttp/psr7

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Affected versions are subject to improper header parsing. An attacker could sneak in a newline (\n) into both the header names and values. While the specification states that \r\n\r\n is used to terminate the header list, many servers in the wild will also accept \n\n. This is a follow-up to CVE-2022-24775 where the fix was incomplete. The issue has been patched in versions 1.9.1 and 2.4.5. There are no known workarounds for this vulnerability. Users are advised to upgrade.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`guzzlehttp/psr7`	all versions	1.9.1`composer require guzzlehttp/psr7:^1.9.1`
🐘Packagist	`guzzlehttp/psr7`	≥ 2.0.0&&< 2.4.5	2.4.5`composer require guzzlehttp/psr7:^2.4.5`

Affected Products

2 products · 4 configurations

fedorafedoraproject

2 versions

3738

Application

psr-7guzzlephp

≥ 2.0.0 && < 2.4.5

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. A…

nvd.nist.govNVDApr 2023

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for guzzlehttp/psr7, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update guzzlehttp/psr7 to 1.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wxmh-65f7-jcvw is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

UbuntuMEDIUM

USN-6670-1Ubuntu USN-6671-1Ubuntu

Frequently Asked Questions

### Impact Improper header parsing. An attacker could sneak in a newline (`\n`) into both the header names and values. While the specification states that `\r\n\r\n` is used to terminate the header list, many servers in the wild will also accept `\n\n`. ### Patches The issue is patched in 1.9.1 and 2.4.5. ### Workarounds There are no known workarounds. ### References * https://www.rfc-editor.org/rfc/rfc7230#section-3.2.4