CVE-2026-123205: Heap Overflow (CVSS 6.5)

Description

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.

Is your site exposed to CVE-2026-123205?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

EPSS — Exploit Prediction

0.0042

Probability of exploitation

0.37%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-122 CWE-122

References

Other References

https://github.com/accel-ppp/accel-ppp/blob/048d31cb446879e0d1a1471b4ab99135a92bf289/accel-pppd/logs/log_tcp.c#L55-L67 https://github.com/accel-ppp/accel-ppp/commit/58e399400c4ef4b71472ab7c2c71c54a677a05a8 https://github.com/accel-ppp/accel-ppp/pull/374 https://github.com/accel-ppp/accel-ppp/releases/tag/1.15.0 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

Frequently Asked Questions

What is CVE-2026-123205? +

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. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-123205? +

CVE-2026-123205 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0042, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-123205? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-8997

vifm is vulnerable to a heap buffer overflow during the history merge process when saving the state file (vifminfo.json). This …

CVE-2026-8484

A heap buffer overflow vulnerability exists in the Jansi JNI "ioctl()" wrapper due to a lack of size verification for …

CVE-2026-6210

A type confusion vulnerability in Qt SVG allows an attacker to cause an application crash via a crafted SVG image. …

CVE-2026-2467

Heap-based Buffer Overflow vulnerability in RTI Connext Professional (Core Libraries) allows Overflow Variables and Tags.This issue affects Connext Professional: from …

CVE-2025-0633

Heap-based Buffer Overflow vulnerability in iniparser_dumpsection_ini() in iniparser allows attacker to read out of bound memory

CVE-2025-3512

There is a Heap-based Buffer Overflow vulnerability in QTextMarkdownImporter. This requires an incorrectly formatted markdown file to be passed to …