CVE-2024-42516Network attack vector

Response splitting via unsafe Content-Type header merging

Published Jul 10, 2025 · Updated Nov 4, 2025

HTTP response splitting in Apache HTTP Server 2.4.0 through 2.4.63 allows remote attackers to inject a second HTTP response. The ap_http_header_filter path in modules/http/http_filters.c merges attacker-controlled Content-Type values into outgoing headers without preserving a single response boundary. Exploitation requires control of a hosted or proxied application's Content-Type response header, allowing a downstream client or intermediary to interpret an injected response separately.

CVSS severity7.5
High
EPSS probability0.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTTP response splitting in Apache HTTP Server 2.4.0 through 2.4.63 allows remote attackers to inject a second HTTP response. The ap_http_header_filter path in modules/http/http_filters.c merges attacker-controlled Content-Type values into outgoing headers without preserving a single response boundary. Exploitation requires control of a hosted or proxied application's Content-Type response header, allowing a downstream client or intermediary to interpret an injected response separately.

The record

CVE
CVE-2024-42516
Published
Jul 10, 2025
Updated
Nov 4, 2025
Vendor
The Apache Software Foundation
Product
Apache HTTP Server
Classifications
CWE-20
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 10, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.4.0 <=2.4.63

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache HTTP Serverversion=2.4.0 <=2.4.63

Published CVSS scores

7.5CISACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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