CVE-2023-29530 | Laminas Diactoros vulnerable to HTTP Multiline Header Termination

Laminas Diactoros provides PSR HTTP Message implementations. In versions 2.18.0 and prior, 2.19.0, 2.20.0, 2.21.0, 2.22.0, 2.23.0, 2.24.0, and 2.25.0, users who create HTTP requests or responses using laminas/laminas-diactoros, when providing a newline at the start or end of a header key or value, can cause an invalid message. This can lead to denial of service vectors or application errors. The problem has been patched in following versions 2.18.1, 2.19.1, 2.20.1, 2.21.1, 2.22.1, 2.23.1, 2.24.1, and 2.25.1. As a workaround, validate HTTP header keys and/or values, and if using user-supplied values, filter them to strip off leading or trailing newline characters before calling `withHeader()`.

Published: 2023-04-24 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-29530 is rated Moderate Risk (55.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.67%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-29530

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-06 0.54% 0.67% +0.13%
2 2026-04-29 0.18% 0.54% +0.36%
3 2025-11-21 — 0.18% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-29530

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]

Weakness enumeration for CVE-2023-29530

GitHub Security Advisory for CVE-2023-29530

GHSA-xv3h-4844-9h36 · Severity: high · Ecosystem: composer — HTTP Multiline Header Termination

Affected software / configurations for CVE-2023-29530

Vendor Product Version Raw CPE
getlaminas laminas-diactoros < 2.18.1 cpe:2.3:a:getlaminas:laminas-diactoros:*:*:*:*:*:*:*:*
getlaminas laminas-diactoros 2.19.0 cpe:2.3:a:getlaminas:laminas-diactoros:2.19.0:*:*:*:*:*:*:*
getlaminas laminas-diactoros 2.20.0 cpe:2.3:a:getlaminas:laminas-diactoros:2.20.0:*:*:*:*:*:*:*
getlaminas laminas-diactoros 2.21.0 cpe:2.3:a:getlaminas:laminas-diactoros:2.21.0:*:*:*:*:*:*:*
getlaminas laminas-diactoros 2.22.0 cpe:2.3:a:getlaminas:laminas-diactoros:2.22.0:*:*:*:*:*:*:*
getlaminas laminas-diactoros 2.23.0 cpe:2.3:a:getlaminas:laminas-diactoros:2.23.0:*:*:*:*:*:*:*
getlaminas laminas-diactoros 2.24.0 cpe:2.3:a:getlaminas:laminas-diactoros:2.24.0:*:*:*:*:*:*:*
getlaminas laminas-diactoros 2.25.0 cpe:2.3:a:getlaminas:laminas-diactoros:2.25.0:*:*:*:*:*:*:*
guzzlephp psr-7 < 1.9.1 cpe:2.3:a:guzzlephp:psr-7:*:*:*:*:*:*:*:*
guzzlephp psr-7 >= 2.0.0, < 2.4.5 cpe:2.3:a:guzzlephp:psr-7:*:*:*:*:*:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*

References for CVE-2023-29530

cvelogic Threat Intelligence