CVE-2026-43002 — horizon
MEDIUMCVE-2026-43002 is a medium-severity (CVSS 5.3) CWE-696 vulnerability in horizon. A fix is available for horizon — see the affected versions and patch details below.
OpenStack Horizon has Incorrect Behavior Order
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-43002.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
horizonReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | horizon | ≥ 25.6&&< 25.7.3 | 25.7.3pip install --upgrade 'horizon==25.7.3' |
Affected Products
horizonopenstackDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for horizon, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update horizon to 25.7.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-43002 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2026-43002 in your dependencies?
Find it across PyPI, including transitive dependencies.