Affects widely used Apache Artemis/ActiveMQ Artemis messaging brokers; unauthenticated session hijack can lead to broad enterprise impact and data/control loss.
CVE-2026-57967
Unauthenticated session hijack in Apache ActiveMQ Artemis (CORE SESSION_REATTACH)
Is CVE-2026-57967 being exploited?
Not confirmed. CVE-2026-57967 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. EPSS currently estimates a 0.69% probability of exploitation in the next 30 days.
How severe is CVE-2026-57967?
CVE-2026-57967 is rated Critical with a CVSS score of 9.8. 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-2026-57967?
Yes. A fix has been recorded for CVE-2026-57967. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-57967 affect?
CVE-2026-57967 affects Apache Artemis 2.50.0 - 2.56.0, Apache ActiveMQ Artemis 1.0.0 - 2.44.0. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-57967?
Upgrade to 2.57.0 immediately; block CORE protocol from untrusted networks.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated remote attacker can send a crafted CORE SESSION_REATTACH to hijack an authenticated session, enabling unauthorized message access and actions.
Immediate action required
- affected>= 1.0.0 and <= 2.44.0
- affected>= 2.50.0 and <= 2.56.0
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.