Stack Buffer Overflow in PJSIP Auth Digest Handling

Publication date: 2026-04-21

Last updated on: 2026-04-23

Assigner: GitHub, Inc.

Description

PJSIP is a free and open source multimedia communication library written in C. In 2.16 and earlier, a stack buffer overflow exists in pjsip_auth_create_digest2() in PJSIP when using pre-computed digest credentials (PJSIP_CRED_DATA_DIGEST). The function copies credential data using cred_info->data.slen as the length without an upper-bound check, which can overflow the fixed-size ha1 stack buffer (128 bytes) if data.slen exceeds the expected digest string length.

CVSS Scores

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Meta Information

Published

2026-04-21

Last Modified

2026-04-23

Generated

2026-07-06

AI Q&A

2026-04-22

EPSS Evaluated

2026-07-05

NVD

CVE-2026-40892

Affected Vendors & Products

Vendor	Product	Version / Range
pjsip	pjsip	to 2.17 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
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).

Attack-Flow Graph

Executive Summary

This vulnerability is a stack buffer overflow in the PJSIP multimedia communication library, specifically in the function pjsip_auth_create_digest2(). It occurs when using pre-computed digest credentials (PJSIP_CRED_DATA_DIGEST). The function copies credential data based on a length value (cred_info->data.slen) without checking if this length exceeds the size of the fixed buffer (128 bytes). If the length is too large, it can overflow the buffer on the stack.

Impact Analysis

The stack buffer overflow can lead to serious security issues such as arbitrary code execution, application crashes, or denial of service. Because the overflow occurs on the stack, an attacker could potentially execute malicious code or disrupt the normal operation of the application using PJSIP.

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