pjsip pjproject Telnet CLI pj_cli_telnet_create stack-based overflow

Summaryinfo

A vulnerability described as critical has been identified in pjsip pjproject. This affects the function pj_cli_telnet_create of the component Telnet CLI. Such manipulation leads to stack-based overflow. This vulnerability is referenced as CVE-2026-57166. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in pjsip pjproject (unknown version) and classified as critical. Affected by this issue is the function pj_cli_telnet_create of the component Telnet CLI. The manipulation with an unknown input leads to a stack-based overflow vulnerability. Using CWE to declare the problem leads to CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-57166 since 06/24/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit.

Applying the patch 4472a31d77a7506ff175dad5abef490f4e31bed1 is able to eliminate this problem.

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Productinfo

Type

• Project Management Software

Vendor

• pjsip

Name

• pjproject

License

• open-source

Website

• Product: https://github.com/pjsip/pjproject/

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