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CVE-2026-56154VulnerabilityPublished Updated

Apache2: Use After Free vulnerability

Affects apache2Source GCVE Database

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Authoritative record:CVE-2026-56154· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical · fixed in 2.4.7-1ubuntu4.22+esm16 : 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 2.4.7-1ubuntu4.22+esm16, 2.4.18-2ubuntu3.17+esm21, 2.4.29-1ubuntu4.27+esm12 +4
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

A patch is available and should be applied immediately. Ubuntu has released fixed package versions for all affected LTS releases, including 14.04 through 26.04. After applying updates, a restart of the apache2 service is required to complete remediation. Users should follow the official Ubuntu security notice USN-8898-1 for detailed update instructions. No additional mitigations are specified or required beyond applying the official patches.

Description

A use-after-free vulnerability exists in the Apache HTTP Server's mod_rewrite module when using lookahead expressions (%{LA-U:HTTP:...}). This flaw affects Apache HTTP Server versions from 2.4.0 through 2.4.68. Exploitation could allow a remote attacker to cause denial of service or execute arbitrary code. Fixes have been released for multiple Ubuntu package versions, and users are advised to update and restart Apache to apply the patches.

References

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