major vulnerability· requires attention

Affects widely used Apache ZooKeeper; can cause persistent ensemble-wide outages and data loss, impacting many distributed systems and services.

Infrastructure

CVE-2026-115448

8.7

High

EPSS n/aPatch available

Deeply nested znodes cause persistent JVM stack-exhaustion DoS in Apache ZooKeeper

exploited

No known exploitation not in CISA KEV as of our last sync

fix

Patch available see the advisory in the references

likelihood

No EPSS score yet

Published 4 Nov 2026Analysed here 5 Nov 2026CVSS scored by the publisher (CNA)

common questions

Is CVE-2026-115448 being exploited?

Not confirmed. CVE-2026-115448 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.

How severe is CVE-2026-115448?

CVE-2026-115448 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2026-115448?

Yes. A fix has been recorded for CVE-2026-115448. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-115448 affect?

CVE-2026-115448 affects Apache ZooKeeper 3.8.0-3.8.7, Apache ZooKeeper 3.9.0-3.9.6, ZooKeeper ensembles. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-115448?

Upgrade to 3.8.8 or 3.9.7; restrict znode creation via ACLs/authentication

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary

technical analysis

affected

Apache ZooKeeper 3.8.0-3.8.7Apache ZooKeeper 3.9.0-3.9.6ZooKeeper ensembles

impact

Attacker with znode-create permission can craft nested znodes to exhaust JVM stack during snapshots, causing persistent DoS across restarts, ensemble spread, and possible data loss.

action required

Immediate action required

affected versions

Apache Software Foundation Apache ZooKeeper

affected>= 3.9.0 and <= 3.9.7
affected>= 3.8.0 and <= 3.8.8

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

cisa ssvc

exploitation: none
automatable: yes
technical impact: partial

Assessed by CISA 4 Nov 2026 (SSVC 2.0.3).

timeline

4 Nov 2026Published
4 Nov 2026CISA SSVC assessment: exploitation none · same day later
4 Nov 2026CVE record last updated · same day later
5 Nov 2026Analysed by vulneraibility.com · 1 day later

how to fix

Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.

references

NVD CVE.org CVE Details Source

2 references in the CVE record: 1 advisory, 1 link

Advisorylists.apache.org /thread.html/p892jm8qw0zqv8z152lpokyt7mp6gc41
Linkopenwall.com /lists/oss-security/2026/11/03/13

sources

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
CISA Vulnrichment (ADP): SSVC decision points
FIRST EPSS: exploit probability and percentile
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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