CVE-2026-57166

What it is

PJSIP is a free and open source multimedia communication library written in C. Prior to commit 4472a31, a stack buffer overflow exists in the PJLIB-UTIL telnet CLI front-end when rendering feedback for an entered command line. Several command-line handling paths write an attacker-influenced amount of data into fixed-size buffers without sufficient bounds checking, so a long command line can overflow them. This affects only applications that enable the telnet CLI front-end (e.g. pj_cli_telnet_create() / --cli-telnet-port). The telnet CLI is an interactive administration interface with no authentication, so any client able to reach it can already issue arbitrary CLI commands. A malformed or overly long command line can overflow a fixed-size stack buffer while rendering command-line feedback, which may lead to application termination. Because reaching this code already requires access to the unauthenticated CLI, the impact beyond that existing access is limited. Applications that do not enable the telnet CLI front-end are not affected. This issue has been patched via commit 4472a31.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-09-04 18:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-09-11 16:53 UTC Last updatedMost recent change to the record

Details

Published

2026-09-04 18:17 UTC

Last modified

2026-09-11 16:53 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-121

Record status

Analyzed

Affected

• Teluu Pjsip ≤ 2.17

Attack profile CVSS 4.0 · 6.3

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

Low