CVE-2026-21869
RCE in llama.cpp server via negative n_discard in JSON input.
Is CVE-2026-21869 being exploited?
Not confirmed. CVE-2026-21869 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 0.52% probability of exploitation in the next 30 days.
How severe is CVE-2026-21869?
CVE-2026-21869 is rated High with a CVSS score of 8.8. 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-2026-21869?
Yes. A fix has been recorded for CVE-2026-21869. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-21869 affect?
CVE-2026-21869 affects llama.cpp server, LLM inference apps using llama.cpp, llama.cpp completion endpoints. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-21869?
Monitor traffic; upgrade when patch released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution via crafted JSON input; memory corruption could crash or execute attacker code.
Monitor only
- affected<= 55d4206c8
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.