# CVE-2026-121510: µD3TN BPv6 heap out-of-bounds write in administrative record parser

Source: https://junglewise.ai/threats/cve-2026-121510-remote-unauthenticated-heap-out-of-bounds-write-in-d3tn-bpv6  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-03. Updated: 2026-11-03  
License: CC BY 4.0 with a link back

CVE-2026-121510 · Severity: high · CVSS 7.5 · Published 2026-11-03

µD3TN is a bundle protocol router that handles network-based message delivery for delay-tolerant networks. A remote attacker can send a specially crafted message to cause a heap memory corruption and crash the router, taking down its availability without needing any credentials or authentication.

Technologies: [D3TN µD3TN](https://junglewise.ai/threats/technologies/d3tn). Vendors: [D3TN](https://junglewise.ai/threats/vendors/d3tn).

## Quick answers

**Is CVE-2026-121510 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-121510 being exploited in the wild.

**How severe is CVE-2026-121510?** High severity, with a CVSS score of 7.5, published 3 November 2026.

**Which products and versions are affected?** D3TN µD3TN.

**Is there a fix for CVE-2026-121510?** No fixed version is recorded yet. Restrict which peers and convergence layers can deliver bundles to the node, limiting exposure to trusted networks until a patch is applied. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-121510 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-121510?** Check whether you run D3TN µD3TN. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix


Restrict which peers and convergence layers can deliver bundles to the node, limiting exposure to trusted networks until a patch is applied.

## Technical details

The BPv6 administrative record parser in components/bundle6/reports.c contains an off-by-one error in the source EID field parsing: it decrements a uint16_t byte counter before testing for zero, causing integer underflow when a zero length is declared. This allows writing up to 65535 attacker-controlled bytes past a one-byte heap allocation. The vulnerability is reachable via any convergence layer (mtcp, smtcp, TCPCLv3) without authentication, as it processes incoming bundles addressed to the local node before any credential validation.

## Affected products

- D3TN µD3TN

## Timeline

- 2026-11-03: disclosed

## References

- [https://gitlab.com/d3tn/ud3tn/-/work_items/289](https://gitlab.com/d3tn/ud3tn/-/work_items/289)

## Related threats

- [µD3TN SPP parser off-by-one heap overflow](https://junglewise.ai/threats/cve-2026-121513-off-by-one-heap-overflow-in-d3tn-v0-15-1-spp-parser-allows)
- [µD3TN memory leak with amplification in BPv6 EID reference handling](https://junglewise.ai/threats/cve-2026-121512-memory-leak-with-amplification-in-d3tn-bpv6-eid-reference)
- [µD3TN BPv6/BPv7 Fragmenter heap buffer out-of-bounds read](https://junglewise.ai/threats/cve-2026-121511-heap-out-of-bounds-read-in-d3tn-bpv6-bpv7-fragmenter-allows)
- [µD3TN BPv6 fragmenter use-after-free in cleanup](https://junglewise.ai/threats/cve-2026-121508-use-after-free-in-d3tn-bpv6-fragmenter-cleanup-allows)
- [µD3TN BPv6 fragmenter double free in block duplication](https://junglewise.ai/threats/cve-2026-121507-double-free-in-d3tn-bpv6-fragmenter-block-duplication-allows)