CVE-2026-43002: An issue was discovered in OpenStack Horizon 25.6 and 25.7 before 25.7.3

This week

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-43002 is a medium-severity flaw (CVSS 5.3) affecting horizon. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 70%)
CISA exploited list	No
Weakness	CWE-696
Published	2026-05-05
Last modified	2026-09-10

Publisher (CNA): MITRE · Vendor: openstack

Last updated 2026-09-10 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-05 17:17 UTCPublished CVE record published
2026-09-10 21:22 UTCUpdated Record last modified

openstack horizon UPGRADE

Affected: >= 25.6.0 and < 25.7.3

Fixed in: 25.7.3

Safe to downgrade to: a release before 25.6.0

1. Check installed version

apt-cache policy horizon || rpm -q horizon || horizon --version

2. UPGRADE to 25.7.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade horizon

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade horizon

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 25.6.0 (Debian / Ubuntu)

apt-cache madison horizon sudo apt install horizon=<VERSION_BEFORE_25.6.0> sudo apt-mark hold horizon

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list horizon sudo dnf downgrade horizon-<VERSION_BEFORE_25.6.0> sudo dnf versionlock add horizon

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-43002?

horizon: upgrade to 25.7.3. Exact commands for each OS are on this page.

Is CVE-2026-43002 being exploited?

CVE-2026-43002 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-43002 affect?

CVE-2026-43002 affects horizon. Severity is medium (CVSS 5.3). 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

How urgent is CVE-2026-43002?

Priority 36/100. Public exploit reference; Remotely exploitable, no login, no user action

Software pages

OpenStack vulnerabilities

Related CVEs

CVE-2026-55748 MEDIUM 6.0 UPGRADE OpenStack Horizon before 25.7.4 produces scripts for OpenStack RC file downloading that may have a crafted pro

References

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