NASA JPL ION-DTN 3.6.2 through 4.2.0 contains a heap-based buffer overflow in the Network Management daemon (nm_mgr) string-formatting logic that allows a malicious or misconfigured agent to trigger an out-of-bounds write by sending deeply nested AMP payloads that exceed fixed-size buffer allocations through unbounded strcat operations. Attackers can transmit oversized AMP reports, tables, or macros over the UDP CLA/AMP path or trigger the flaw locally via interactive UI rendering to crash nm_mgr and cause a denial of service halting telemetry collection and operator visibility.
0.5% estimated probability of exploitation activity in the next 30 days; 42nd percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
CISA's assessment (SSVC)
Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-12. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
Show the promptExplain CVE-2026-123999 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-123999?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-123999?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-123999 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.
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