Is CVE-2026-34356 in the CISA KEV catalog?

No. CVE-2026-34356 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-34356?

CVE-2026-34356 has a CVSS v3 base score of 7.5 (Moderate).

What is the EPSS score for CVE-2026-34356?

CVE-2026-34356 has an EPSS score of 0.68% (48th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-34356?

Upgrade apache2 on debian 11 to 2.4.67-1~deb11u3 or later. Fixes are available for 42 affected products.

CVE & CISA-KEV Catalog

CVE-2026-34356

MEDIUM

7.5

CVSS v3

NVD

Description

Heap-based Buffer Overflow vulnerability in Apache HTTP Server with malicious backend servers and ProxyPassReverseCookie* This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67. Users are recommended to upgrade to version 2.4.68, which fixes the issue.

CWE-122Heap-based Buffer Overflow

How to fix

Remediation Available

apache2Debian

Fixed in:2.4.67-1~deb11u3CVE-2026-34356

Fixed in:2.4.68-1CVE-2026-34356

httpdRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpdRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-coreRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-coreRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-core-debuginfoRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-core-debuginfoRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-debuginfoRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-debuginfoRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-debugsourceRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-debugsourceRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-develRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-develRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-filesystemRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-filesystemRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-manualRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-manualRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-toolsRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-toolsRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-tools-debuginfoRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

httpd-tools-debuginfoRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_ldapRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_ldapRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_ldap-debuginfoRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_ldap-debuginfoRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_luaRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_luaRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_lua-debuginfoRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_lua-debuginfoRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_proxy_htmlRocky

Fixed in:1:2.4.63-13.el10_2.4RHSA-2026:34109

mod_proxy_htmlRed Hat / RHEL

Fixed in:1:2.4.63-13.el10_2.4RHSA-2026:34109

mod_proxy_html-debuginfoRocky

Fixed in:1:2.4.63-13.el10_2.4RHSA-2026:34109

mod_proxy_html-debuginfoRed Hat / RHEL

Fixed in:1:2.4.63-13.el10_2.4RHSA-2026:34109

mod_sessionRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_sessionRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_session-debuginfoRed Hat / RHEL

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_session-debuginfoRocky

Fixed in:0:2.4.63-13.el10_2.4RHSA-2026:34109

mod_sslRocky

Fixed in:1:2.4.63-13.el10_2.4RHSA-2026:34109

mod_sslRed Hat / RHEL

Fixed in:1:2.4.63-13.el10_2.4RHSA-2026:34109

mod_ssl-debuginfoRed Hat / RHEL

Fixed in:1:2.4.63-13.el10_2.4RHSA-2026:34109

mod_ssl-debuginfoRocky

Fixed in:1:2.4.63-13.el10_2.4RHSA-2026:34109

Apache Lounge httpdWindows application

Affected:2.4.0 2.4.68Fixed in:2.4.68Apache Lounge

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

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

0.68%probability of exploitation in 30 days

48thpercentile

Moderate risk: more likely to be exploited than 48% of all known CVEs.

References

Vendor Advisory1

httpd.apache.org

Mailing List1

openwall.com

Related Vulnerabilities

Other CWE-122 (Heap-based Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2015-3113	Critical	9.8	100%	KEV	Fix
CVE-2024-26256	High	7.8	88%	-	Fix
CVE-2020-25687	Medium	5.9	87%	-	Fix
CVE-2009-3459	High	8.8	86%	KEV	Fix
CVE-2021-21017	High	8.8	86%	KEV	-
CVE-2020-25683	Medium	5.9	86%	-	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 2026-06-09.