IBM MQ is widely used enterprise messaging middleware; authenticated RCE/DoS on HPE NonStop MQ can disrupt critical infrastructure and enterprise services.
CVE-2026-10858
Authenticated heap underflow in IBM MQ for HPE NonStop allows DoS or RCE
Is CVE-2026-10858 being exploited?
Not confirmed. CVE-2026-10858 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 0.33% probability of exploitation in the next 30 days.
How severe is CVE-2026-10858?
CVE-2026-10858 is rated Critical with a CVSS score of 9.9. 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-2026-10858?
Not known from our data. No patch reference has been recorded for CVE-2026-10858, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-10858 affect?
CVE-2026-10858 affects IBM MQ for HPE NonStop 8.1.0 through 8.1.0.40. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-10858?
Apply vendor update ASAP; restrict MQ access and monitor message traffic.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated attacker sending multi-segment messages can trigger a heap buffer underflow to cause denial of service or execute arbitrary code on the MQ server.
Immediate action required
- affected>= 8.1.0 and <= 8.1.0.40
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.