CVE-2026-8855
RCE and DoS on IBM HTTP Server with TLS mutual authentication.
Is CVE-2026-8855 being exploited?
Not confirmed. CVE-2026-8855 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 0.46% probability of exploitation in the next 30 days.
How severe is CVE-2026-8855?
CVE-2026-8855 is rated High with a CVSS score of 8.1. 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-2026-8855?
Yes. A fix has been recorded for CVE-2026-8855. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-8855 affect?
CVE-2026-8855 affects IBM HTTP Server 8.5, IBM HTTP Server 9.0. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-8855?
Patch when available; harden/disable mutual TLS on exposed endpoints
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
RCE/DoS via TLS mutual-auth config; attacker can execute code on the server.
Immediate action required
- affected>= 8.5.0 and <= Interim Fix 002
- affected9.0
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.