Is CVE-2026-43951 in the CISA KEV catalog?

No. CVE-2026-43951 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-43951?

CVE-2026-43951 has a CVSS v3 base score of 6.5 (Moderate).

What is the EPSS score for CVE-2026-43951?

CVE-2026-43951 has an EPSS score of 0.53% (41th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-43951?

Upgrade apache2 on debian 11 to 2.4.67-1~deb11u3 or later. Fixes are available for 7 affected products.

CVE & CISA-KEV Catalog

CVE-2026-43951

MEDIUM

6.5

CVSS v3

NVD

Description

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-125Out-of-bounds Read

How to fix

Remediation Available

apache2Debian

Fixed in:2.4.67-1~deb11u3CVE-2026-43951

Fixed in:2.4.68-1CVE-2026-43951

mod_http2Rocky

Fixed in:0:2.0.29-4.el10_2.2RHSA-2026:34355

mod_http2Red Hat / RHEL

Fixed in:0:2.0.29-4.el10_2.2RHSA-2026:34355

mod_http2-debuginfoRocky

Fixed in:0:2.0.29-4.el10_2.2RHSA-2026:34355

mod_http2-debuginfoRed Hat / RHEL

Fixed in:0:2.0.29-4.el10_2.2RHSA-2026:34355

mod_http2-debugsourceRocky

Fixed in:0:2.0.29-4.el10_2.2RHSA-2026:34355

mod_http2-debugsourceRed Hat / RHEL

Fixed in:0:2.0.29-4.el10_2.2RHSA-2026:34355

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Exploit Intelligence

0.53%probability of exploitation in 30 days

41stpercentile

Moderate risk: more likely to be exploited than 41% of all known CVEs.

References

Vendor Advisory1

httpd.apache.org

Third-Party Advisory1

openwall.com

Related Vulnerabilities

Other CWE-125 (Out-of-bounds Read) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2014-0160	High	7.5	100%	KEV	Fix
CVE-2025-5777	High	7.5	100%	KEV + Ransom	Fix
CVE-2021-4034	High	7.8	95%	KEV	Fix
CVE-2023-21769	High	7.5	92%	-	Fix
CVE-2023-49285	High	8.6	89%	-	Fix
CVE-2020-8794	Critical	9.8	89%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-11.