CVE-2026-57941

CRITICAL

9.8

CVSS v3

Description

Use After Free vulnerability in Apache HTTP Server's mod_http2 via shared session->bbtmp re-entrancy This issue affects Apache HTTP Server: from 2.4.0 through 2.4.68.

CWE-416Use After Free

How to fix

Remediation Available

apache2Debian

Fixed in:2.4.69-1CVE-2026-57941

apache2Ubuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

Fixed in:2.4.18-2ubuntu3.17+esm21USN-8898-1

Fixed in:2.4.29-1ubuntu4.27+esm12USN-8898-1

Fixed in:2.4.41-4ubuntu3.23+esm8USN-8898-1

Fixed in:2.4.52-1ubuntu4.24USN-8898-1

Fixed in:2.4.58-1ubuntu8.16USN-8898-1

apache2-binUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

Fixed in:2.4.18-2ubuntu3.17+esm21USN-8898-1

Fixed in:2.4.29-1ubuntu4.27+esm12USN-8898-1

Fixed in:2.4.41-4ubuntu3.23+esm8USN-8898-1

Fixed in:2.4.52-1ubuntu4.24USN-8898-1

Fixed in:2.4.58-1ubuntu8.16USN-8898-1

apache2-devUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

Fixed in:2.4.18-2ubuntu3.17+esm21USN-8898-1

Fixed in:2.4.29-1ubuntu4.27+esm12USN-8898-1

Fixed in:2.4.41-4ubuntu3.23+esm8USN-8898-1

Fixed in:2.4.52-1ubuntu4.24USN-8898-1

Fixed in:2.4.58-1ubuntu8.16USN-8898-1

apache2-mpm-eventUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

apache2-mpm-itkUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

apache2-mpm-preforkUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

apache2-mpm-workerUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

apache2-ssl-devUbuntu

Fixed in:2.4.29-1ubuntu4.27+esm12USN-8898-1

Fixed in:2.4.41-4ubuntu3.23+esm8USN-8898-1

Fixed in:2.4.52-1ubuntu4.24USN-8898-1

Fixed in:2.4.58-1ubuntu8.16USN-8898-1

apache2-suexecUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

apache2-suexec-customUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

Fixed in:2.4.18-2ubuntu3.17+esm21USN-8898-1

Fixed in:2.4.29-1ubuntu4.27+esm12USN-8898-1

Fixed in:2.4.41-4ubuntu3.23+esm8USN-8898-1

Fixed in:2.4.52-1ubuntu4.24USN-8898-1

Fixed in:2.4.58-1ubuntu8.16USN-8898-1

apache2-suexec-pristineUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

Fixed in:2.4.18-2ubuntu3.17+esm21USN-8898-1

Fixed in:2.4.29-1ubuntu4.27+esm12USN-8898-1

Fixed in:2.4.41-4ubuntu3.23+esm8USN-8898-1

Fixed in:2.4.52-1ubuntu4.24USN-8898-1

Fixed in:2.4.58-1ubuntu8.16USN-8898-1

apache2-utilsUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

Fixed in:2.4.18-2ubuntu3.17+esm21USN-8898-1

Fixed in:2.4.29-1ubuntu4.27+esm12USN-8898-1

Fixed in:2.4.41-4ubuntu3.23+esm8USN-8898-1

Fixed in:2.4.52-1ubuntu4.24USN-8898-1

Fixed in:2.4.58-1ubuntu8.16USN-8898-1

apache2.2-binUbuntu

Fixed in:2.4.7-1ubuntu4.22+esm16USN-8898-1

libapache2-mod-macroUbuntu

Fixed in:1:2.4.7-1ubuntu4.22+esm16USN-8898-1

libapache2-mod-mdUbuntu

Fixed in:2.4.41-4ubuntu3.23+esm8USN-8898-1

Fixed in:2.4.52-1ubuntu4.24USN-8898-1

Fixed in:2.4.58-1ubuntu8.16USN-8898-1

libapache2-mod-proxy-htmlUbuntu

Fixed in:1:2.4.7-1ubuntu4.22+esm16USN-8898-1

libapache2-mod-proxy-uwsgiUbuntu

Fixed in:2.4.41-4ubuntu3.23+esm8USN-8898-1

Fixed in:2.4.52-1ubuntu4.24USN-8898-1

Fixed in:2.4.58-1ubuntu8.16USN-8898-1

httpdWindows application

Affected:2.4.0 2.4.69Fixed in:2.4.69Apache Lounge

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

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

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.60%probability of exploitation in 30 days

47thpercentile

Moderate risk: more likely to be exploited than 47% of all known CVEs.

References

Vendor Advisory1

httpd.apache.org

Third-Party Advisory1

openwall.com

Related Vulnerabilities

Other CWE-416 (Use After Free) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-0708	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-31166	Critical	9.8	100%	KEV	Fix
CVE-2015-5119	Critical	9.8	99%	KEV	-
CVE-2010-3962	High	8.1	97%	KEV	-
CVE-2021-34833	High	7.8	96%	-	-
CVE-2015-0313	Critical	9.8	95%	KEV	Fix

Common questions

How do I fix CVE-2026-57941?

Published advisories record a fix for 19 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2026-57941 being actively exploited?

Not that we know of. CVE-2026-57941 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.60% is the estimated probability that it will be exploited in the next 30 days. That is higher than 47% of all scored CVEs.

How severe is CVE-2026-57941?

CVE-2026-57941 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-57941 affect?

Published advisories record a fix for apache2 (Debian), apache2 (Ubuntu), apache2-bin (Ubuntu), apache2-dev (Ubuntu), and 15 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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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 2026-10-05.