CVE-2026-57164
Received Received - Intake

Heap Buffer Overflow in PJSIP PJLIB-UTIL HTTP Client

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: GitHub, Inc.

Description
PJSIP is a free and open source multimedia communication library written in C. Prior to commit 8d5956a, a heap buffer overflow exists in the PJLIB-UTIL HTTP client (http_client.c) when buffering an HTTP response body. This affects applications that use the PJLIB-UTIL HTTP client to receive a whole response body at once (a completion callback with no incremental on_data_read callback). When growing the response buffer, an incorrect size calculation based on the server-supplied Content-Length can leave the buffer too small, causing response data to be written past the end of the allocation. A malicious or man-in-the-middle HTTP server can trigger this with a crafted response; impact may range from unexpected application termination to memory corruption. Applications that consume the response incrementally (via on_data_read), or that only connect to trusted servers, are not affected. This issue has been patched via commit 8d5956a.

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Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-05
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
CVE-2026-57164
EUVD
EUVD-2026-71658

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
pjsip pjlib-util to 8d5956a (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-122 A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Attack-Flow Graph

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Executive Summary

This is a heap buffer overflow in the PJLIB-UTIL HTTP client of PJSIP. It occurs when buffering an HTTP response body if the server-supplied Content-Length is incorrect. The buffer grows based on this length but may still be too small, causing data to be written past allocated memory. A malicious server can exploit this to cause crashes or memory corruption.

Detection Guidance

Detecting this vulnerability requires checking if your system uses a vulnerable version of PJSIP's PJLIB-UTIL HTTP client. Inspect the version of PJSIP in use and verify if it is prior to commit 8d5956a. Check application logs for HTTP client usage patterns that buffer entire response bodies without incremental callbacks.

Impact Analysis

Impact ranges from application crashes to memory corruption. If exploited, it could allow attackers to execute arbitrary code or cause denial of service. Only affects apps using the HTTP client to receive full response bodies at once without incremental callbacks.

Mitigation Strategies

Immediately update PJSIP to a version that includes commit 8d5956a or later. If updating is not possible, disable the PJLIB-UTIL HTTP client in affected applications or restrict connections to trusted HTTP servers only. Monitor network traffic for suspicious HTTP responses.

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