# CVE-2026-124000: ION-DTN 2.1.0-4.2.0 Heap Buffer Under-allocation DoS in amsd

Status: published. Published: 2026-11-09. Updated: 2026-11-09.

NASA JPL ION-DTN 2.1.0 through 4.2.0 contains a heap buffer under-allocation vulnerability in the Asynchronous Message Service daemon (amsd) that allows a rogue or misconfigured peer to trigger an out-of-bounds write by sending crafted Meta-AMS (MAMS) configuration management messages that are processed without cryptographic authentication. Attackers can exploit the insufficient buffer size calculation for the internal state-event object to crash the active Configuration Server thread, causing a denial of service and potentially destabilizing subsequent shared-memory allocations in amsd.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/nasa-jpl/ION-DTN/releases/tag/ion-open-source-4.2.1-a.2

## Affected products and versions

- nasa-jpl / ION-DTN (nasa-jpl/ION-DTN): ≥ 2.1.0; ≤ 4.2.0 (affected, semver); 4.2.1-a.2 (unaffected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.9 (medium); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-122

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/nasa-jpl/ION-DTN/security/advisories/GHSA-h28r-fr59-c79c (CNA: VulnCheck; vendor-advisory)

- https://github.com/nasa-jpl/ION-DTN/releases/tag/ion-open-source-4.2.1-a.2 (CNA: VulnCheck; release-notes, patch)

- https://www.vulncheck.com/advisories/ion-dtn-heap-buffer-under-allocation-dos-in-amsd (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-124000; retrieved 2026-11-09; source updated 2026-11-09

Revision: c140eabf564681a0e100128014874eb9b9fc74ce6393aa3b53f64ff42772b046

Canonical: https://y2.dev/cve/CVE-2026-124000

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