# CVE-2026-121513: µD3TN SPP parser off-by-one heap overflow

Source: https://junglewise.ai/threats/cve-2026-121513-off-by-one-heap-overflow-in-d3tn-v0-15-1-spp-parser-allows  
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-2026-121513 · Severity: high · CVSS 7.5 · Published 2026-11-03

µD3TN is a delay-tolerant networking daemon used to exchange data in challenged communication environments. An off-by-one error in the SPP (Stream Protocol Processor) parser allows an unauthenticated attacker to send a crafted network packet that crashes the daemon, causing a denial of service and disrupting data transfer operations.

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

## Quick answers

**Is CVE-2026-121513 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-121513 being exploited in the wild.

**How severe is CVE-2026-121513?** High severity, with a CVSS score of 7.5, published 3 November 2026.

**Which products and versions are affected?** D3TN µD3TN v0.15.1 and earlier (master branch at commit ea56c6fb695044b1d05b965b545760ad36da25a1).

**Is there a fix for CVE-2026-121513?** No fixed version is recorded yet. Check the vendor's advisory in the references below. 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-2026-121513 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-121513?** Check whether you run D3TN µD3TN at an affected version. 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.

## Technical details

An off-by-one error in the SPP timecode parser's fractional octet count extraction leads to a heap buffer overflow in the parser state's fractional_buf. The vulnerability exists in the handling of SPP frames with secondary headers and is triggered via a malformed P-field. An unauthenticated attacker on the network can reliably exploit this to cause process termination; no authentication is required and the attack requires only network connectivity to the SPP port.

## Affected products

- D3TN µD3TN v0.15.1 and earlier (master branch at commit ea56c6fb695044b1d05b965b545760ad36da25a1)

## Timeline

- 2026-11-03: disclosed

## References

- [https://gitlab.com/d3tn/ud3tn/-/work_items/288](https://gitlab.com/d3tn/ud3tn/-/work_items/288)

## Related threats

- [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 heap out-of-bounds write in administrative record parser](https://junglewise.ai/threats/cve-2026-121510-remote-unauthenticated-heap-out-of-bounds-write-in-d3tn-bpv6)
- [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)