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CVE-2026-57941VulnerabilityPublished Updated

Apache2: Use After Free vulnerability

Affects apache2Source GCVE Database

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Authoritative record:CVE-2026-57941· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical · fixed in 2.4.29-1ubuntu4.27+esm12 : patch apache2 as a priority.

Data as of 10 Nov 2026, 06:10 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 2.4.29-1ubuntu4.27+esm12, 2.4.41-4ubuntu3.23+esm8, 2.4.52-1ubuntu4.24 +2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 26.10apache2pkg:deb/ubuntu/apache2?arch=source&distro=stonkingOther threatsAffected
  • =2.4.66-2ubuntu2
  • =2.4.68-1ubuntu4
  • =2.4.68-1ubuntu6.1
Fixed in–
Ubuntu 26.04 LTSapache2pkg:deb/ubuntu/apache2?arch=source&distro=resoluteOther threatsAffected
  • <2.4.66-2ubuntu2.5
Fixed in
  • 2.4.66-2ubuntu2.5
Ubuntu 24.04 LTSapache2pkg:deb/ubuntu/apache2?arch=source&distro=nobleOther threatsAffected
  • <2.4.58-1ubuntu8.16
Fixed in
  • 2.4.58-1ubuntu8.16
Ubuntu 22.04 LTSapache2pkg:deb/ubuntu/apache2?arch=source&distro=jammyOther threatsAffected
  • <2.4.52-1ubuntu4.24
Fixed in
  • 2.4.52-1ubuntu4.24
Ubuntu Pro 20.04 LTSapache2pkg:deb/ubuntu/apache2?arch=source&distro=esm-infra/focalOther threatsAffected
  • <2.4.41-4ubuntu3.23+esm8
Fixed in
  • 2.4.41-4ubuntu3.23+esm8
Ubuntu Pro 18.04 LTSapache2pkg:deb/ubuntu/apache2?arch=source&distro=esm-infra/bionicOther threatsAffected
  • <2.4.29-1ubuntu4.27+esm12
Fixed in
  • 2.4.29-1ubuntu4.27+esm12

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Apply the official security patches provided by Ubuntu as listed in the security notice USN-8898-1. The fixed versions are 2.4.29-1ubuntu4.27+esm12, 2.4.41-4ubuntu3.23+esm8, 2.4.52-1ubuntu4.24, 2.4.58-1ubuntu8.16, and 2.4.66-2ubuntu2.5. No additional mitigation is required beyond updating to these patched versions.

Description

A critical use-after-free vulnerability exists in Apache HTTP Server's mod_http2 module due to shared session->bbtmp re-entrancy. This affects Apache HTTP Server versions from 2.4.0 through specific Ubuntu package versions prior to fixed releases. The flaw allows remote attackers to cause high impact including full confidentiality, integrity, and availability compromise. Patches are available and should be applied promptly.

References

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