---
id: "CVE-2026-123205"
kind: "vulnerability"
aliases: ["CVE-2026-123205"]
title: "accel-ppp: remote heap overflow in log targets crashes the VPN daemon"
severity: "high"
cvss: 8.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["accel-ppp", "l2tp", "linux", "package", "vpn-server"]
not_affected_if: ["not-running-accel-ppp", "verbose-logging-disabled"]
published_at: "2026-11-05T19:17:19+00:00"
first_seen_at: "2026-11-05T19:40:36+00:00"
updated_at: "2026-11-05T19:42:52+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123205", "first_seen_at": "2026-11-05T19:40:36+00:00"}]
exploit_sources: []
---

# accel-ppp: remote heap overflow in log targets crashes the VPN daemon

accel-ppp, a VPN server daemon for PPP and L2TP connections, has a heap buffer overflow in its tcp, syslog and pgsql log targets. An unauthenticated remote peer can corrupt heap memory by sending an L2TP Start-Control-Connection-Request with many string AVPs while verbose logging is enabled, which crashes the daemon.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed accel-ppp version and see whether it is older than `1.15.0`.
- Check the accel-ppp config for verbose logging and for the tcp, syslog or pgsql log targets.

## Fix

- Move accel-ppp to `1.15.0` or later.

## Timeline

- 2026-11-05T19:40:36+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123205

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/accel-ppp-before-1.15.0-heap-based-buffer-overflow-via-oversized-log-lines-in-log-tcp-log-syslog-log-pgsql
- [fix] Patch: github.com https://github.com/accel-ppp/accel-ppp/commit/58e399400c4ef4b71472ab7c2c71c54a677a05a8
- [fix] Release notes: github.com https://github.com/accel-ppp/accel-ppp/releases/tag/1.15.0

## From the sources

accel-ppp before 1.15.0 contains a heap buffer overflow vulnerability in the tcp, syslog and pgsql log targets that allows unauthenticated remote peers to overflow fixed heap buffers by producing log lines exceeding LOG_MAX_SIZE. Attackers within client-ip-range can send an L2TP Start-Control-Connection-Request with many string AVPs when verbose logging is enabled to corrupt heap memory and crash the daemon.

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