CVE-2026-84851
Crafted Ion data can trigger recursion in Amazon Ion-C and crash applications (DoS).
Is CVE-2026-84851 being exploited?
Not confirmed. CVE-2026-84851 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 0.34% probability of exploitation in the next 30 days.
How severe is CVE-2026-84851?
CVE-2026-84851 is rated High with a CVSS score of 8.7. 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-2026-84851?
Yes. A fix has been recorded for CVE-2026-84851. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-84851 affect?
CVE-2026-84851 affects amazon-ion/ion-c < 1.1.6, Applications and services linking amazon-ion/ion-c, Any software parsing untrusted Ion data. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-84851?
Upgrade to ion-c v1.1.6+, validate/sanitize Ion input, rebuild and redeploy affected services.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote unauthenticated attacker can send crafted Ion data to exhaust the native call stack and crash applications (denial of service).
Patch when possible
- affected< 1.1.6
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.