Cyber Resilience

CVE-2026-43951

Memory Safety in Apache Http Server 2.4.0 – 2.4.67

Published
08 June 2026
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS Score 0.0054 43th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-43951 is a medium-severity Out-of-bounds Read (CWE-125) vulnerability in Apache Http Server. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 43th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-2 (Flaw Remediation) and CM-7 (Least Functionality) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Out-of-bounds Read vulnerability in Apache HTTP Server with mod_headers and mod_mime and multiple response languages. This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Why these techniques?

Out-of-bounds read in public-facing Apache HTTP Server directly enables remote exploitation of a network-accessible service.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-33857Same product: Apache Http Server
CVE-2026-34032Same product: Apache Http Server
CVE-2026-44185Same product: Apache Http Server
CVE-2026-41607Same vendor: Apache
CVE-2023-25690Same product: Apache Http Server
CVE-2026-58023Same vendor: Apache
CVE-2023-43622Same product: Apache Http Server
CVE-2026-58662Same vendor: Apache
CVE-2026-41604Same vendor: Apache
CVE-2026-64609Same vendor: Apache

Affected Assets

apache
http server
2.4.0 — 2.4.67

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-2 Flaw Remediation
  • CM-7 Least Functionality
Detect
Catch it (NIST detect / respond)
  • RA-5 Vulnerability Monitoring and Scanning
Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly requires timely patching of Apache HTTP Server to a version >2.4.67, eliminating the out-of-bounds read in mod_headers/mod_mime.

prevent

Enforces least functionality by disabling or restricting unneeded modules (mod_headers, mod_mime) and multi-language response handling that trigger the flaw.

detect

Requires continuous vulnerability scanning to identify running instances of vulnerable Apache 2.4.0-2.4.67 before exploitation.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices such as bounds checking and memory-safe languages directly prevent out-of-bounds reads.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing out-of-bounds read flaws.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Security testing in development and acceptance includes fuzzing and static analysis that detect out-of-bounds read defects before release.

A.8.15 Logging partial match
detects

Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.

prevents

Secure development life cycle mandates input validation and bounds checking that directly prevent out-of-bounds reads.

prevents

Application security requirements include explicit bounds and memory-safety specifications that mitigate buffer over-reads.

prevents

Secure system architecture and engineering principles require memory-safe design patterns and runtime protections against out-of-bounds access.

prevents

Secure coding standards explicitly forbid unsafe pointer arithmetic and mandate bounds-checked reads, eliminating CWE-125.

References