# CVE-2023-29197: Improper header name validation in guzzlehttp/psr7

> Attackers can inject newlines into HTTP headers due to improper validation, potentially bypassing security controls in applications using this PHP library.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Apr 2023
- **Updated:** 13 Feb 2025
- **Also known as:** CLSA-2026-1788333194, DEBIAN-CVE-2023-29197, DLA-3705-1, GHSA-wxmh-65f7-jcvw, UBUNTU-CVE-2023-29197, USN-6671-1

## What is CVE-2023-29197?

CVE-2023-29197 is a medium-severity vulnerability in Fedoraproject Fedora, published on 17 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-436 (Interpretation Conflict)

## Which versions are affected by CVE-2023-29197?

4 open source packages ship an affected version, including guzzlehttp/psr7. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `guzzlehttp/psr7` | Packagist | All versions | 1.9.1 |
| `guzzlehttp/psr7` | Packagist | All versions | 1.9.1 |
| `guzzlehttp/psr7` | Packagist | From 2.0.0 | 2.4.5 |
| `guzzlehttp/psr7` | Packagist | From 2.0.0 | 2.4.5 |

Products: Fedoraproject Fedora, Guzzlephp Psr-7.

## How do I fix CVE-2023-29197?

Upgrade guzzlehttp/psr7 to a fixed version for your release line: 1.9.1 or 2.4.5.

## Is CVE-2023-29197 being exploited?

There is no known exploitation of CVE-2023-29197 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-29197 and fix it if it is affected.

What it is: CVE-2023-29197 is a medium-severity vulnerability in Fedoraproject Fedora, published on 17 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-29197 in the wild and no public exploit code.

Affected packages and fixed versions:
- guzzlehttp/psr7 (Packagist): affected all versions; fixed in 1.9.1
- guzzlehttp/psr7 (Packagist): affected all versions; fixed in 1.9.1
- guzzlehttp/psr7 (Packagist): affected from 2.0.0; fixed in 2.4.5
- guzzlehttp/psr7 (Packagist): affected from 2.0.0; fixed in 2.4.5

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-29197/ (Markdown: https://insights.sbomify.com/CVE-2023-29197/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-29197
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-29197
- OSV: https://osv.dev/vulnerability/CVE-2023-29197

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-29197/
Summaries are generated and may contain mistakes; the official description above is the record.