CVE-2023-29197

Improper header name validation in guzzlehttp/psr7

HIGH
7.5
CVSS Score
Published: April 17, 2023 at 09:08 PM UTC
Updated: June 17, 2026 at 05:49 AM UTC
3 products affected across 3 vendorsFedoraPsr 7PSR7

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Severity
HIGH7.5
Exploit prediction
EPSS 1%

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.9.12.0.0 ≤ v < 2.4.5
Affected range stops below 1.9.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 2.4.5, so it looks safe — our inference, not a vendor statement
60%
v < 1.9.1v < 2.4.5
Affected range stops below 1.9.1, so it looks safe — our inference, not a vendor statement
Affected range stops below 2.4.5, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-436

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