CVE-2026-43002 OpenStack Horizon has Incorrect Behavior Order

What is CVE-2026-43002?

CVE-2026-43002 is a medium-severity denial of service vulnerability in OpenStack Horizon, published on 5 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An issue was discovered in OpenStack Horizon 25.6 and 25.7 before 25.7.3. There is a write operation to the session storage backend before authentication and thus storage can be exhausted by unauthenticated requests. This is a regression of the CVE-2014-8124 fix.

Weakness: CWE-696

Which versions are affected by CVE-2026-43002?

3 open source packages ship an affected version, including horizon. It affects 1 product.

Products include Openstack Horizon.

How do I fix CVE-2026-43002?

Upgrade horizon to 25.7.3 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-43002 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43002 exists.

Other vulnerabilities in OpenStack Horizon

• CVE-2012-2144 OpenStack Horizon Session Fixation Medium 6.8
• CVE-2022-45582 Horizon Web Dashboard Open Redirect vulnerability Medium 6.1
• CVE-2026-55748 OpenStack Horizon RC file generation does not escape special characters in project names Medium 6.0
• CVE-2012-3540 Open redirect in n/a Medium 5.8
• CVE-2013-4471 Auth bypass in n/a Medium 5.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-43002, GHSA-vxvf-xvm3-p8j5, PYSEC-2026-2520, UBUNTU-CVE-2026-43002.