Apache ActiveMQ, Apache ActiveMQ KahaDB: Oversized client identifier strings poison the KahaDB journal
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 6.3.3, 5.19.12
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 6.3.3, 5.19.12.
- Exploitation?/40Exploitation: unknown (data gap). No CISA SSVC exploitation rating yet
- Exposure?/25Exposure: unknown (data gap). No advisory context yet
- Reach10/20Affects Maven packages
- Severity?/10Severity: unknown (data gap). No CVSS score or vendor rating
- No patch0/5No signal
What would change the score
- Would score about 65 if added to CISA KEV
- Would score about 60 if CISA's SSVC rates exploitation active
- Would score about 32 if advisories confirm default setups are exposed
CVE-2026-111821 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It affects Apache ActiveMQ and Apache ActiveMQ KahaDB; fixed in 6.3.3 and 5.19.12.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 10/100 · provisional
- Fix
- Fixed in 6.3.3, 5.19.12
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Apache ActiveMQ and its KahaDB persistence component are affected. An authenticated user who can create a durable subscription can send an oversized client ID and subscription name, which can crash the broker and leave it unable to recover.
Read the original description
Improper input validation vulnerability in Apache ActiveMQ, Apache ActiveMQ KahaDB. A user can create a durable subscription with a clientId and subscription name that have a combined length > 65,535 (while separately being shorter) on a broker using KahaDB which can cause the broker to shutdown and be unrecoverable. This issue affects Apache ActiveMQ: from 6.0.0 before 6.3.3, before 5.19.12; Apache ActiveMQ KahaDB: from 6.0.0 before 6.3.3, before 5.19.12. Users are recommended to upgrade to version 6.4.0, 6.3.3 or 5.19.12, which fixes the issue.
Impact
- Widely used
4 packages depend on org.apache.activemq:apache-activemq.Source: deps.dev
What to do
Upgrade to a fixed version: 6.3.3, 5.19.12.
Timeline
- CVE published
- Record last updated
- First seen by cve.now
Affected versions
- org.apache.activemq:apache-activemqMaven
From 6.0.0 · fixed in 6.3.3; fixed in 5.19.12
- org.apache.activemq:activemq-kahadb-storeMaven
From 6.0.0 · fixed in 6.3.3; fixed in 5.19.12
Evidence 2
- Advisory
- Link
Corrections
None so far.
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Questions about CVE-2026-111821
Is CVE-2026-111821 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-111821?
org.apache.activemq:apache-activemq (Maven): from 6.0.0 before 6.3.3; before 5.19.12. org.apache.activemq:activemq-kahadb-store (Maven): from 6.0.0 before 6.3.3; before 5.19.12.Source: cve.now feed data
How do I fix CVE-2026-111821?
Upgrade to a fixed version: 6.3.3, 5.19.12.Source: cve.now feed data