Amazon Ion-C vulnerabilities

2 CVEs affecting Amazon Ion-C, 0 known to be exploited (CISA KEV), with EPSS scores. Latest: CVE-2026-84851, published 2026-09-03.

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Known exploited (CISA KEV) first, then by EPSS exploit probability.

• CVE-2026-84851, published 2026-09-03. High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days. An uncontrolled recursion issue exists in Amazon Ion-C versions before 1.1.6 that might allow a remote unauthenticated actor to craft Ion data that exhausts the native call stack and crashes the…
• CVE-2025-12829, published 2025-11-07. Medium severity, CVSS 6.2. EPSS: 0.2% chance of exploitation in the next 30 days. An uninitialized stack read issue exists in Amazon Ion-C versions <v1.1.4 that may allow a threat actor to craft data and serialize it to Ion text in such a way that sensitive data in memory could be…