CVE-2026-56001
Heap overflow in libXfont2 allows code execution in X server.
Is CVE-2026-56001 being exploited?
Not confirmed. CVE-2026-56001 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 0.39% probability of exploitation in the next 30 days.
How severe is CVE-2026-56001?
CVE-2026-56001 is rated High with a CVSS score of 8.5. 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-2026-56001?
Yes. A fix has been recorded for CVE-2026-56001. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-56001 affect?
CVE-2026-56001 affects libXfont2 < 2.0.8, X.Org X Server (X11), Linux/Unix desktops and appliances running X11. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-56001?
Upgrade libXfont2 to 2.0.8+ and restrict or block external X server access.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attackers with access to the X Server can trigger a heap overflow to execute arbitrary code as the X server user.
Immediate action required
- affected< 2.0.8
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.