PJSIP: Stack overflow handling Service-Route headers in a registration response

Description

PJSIP is a free and open source multimedia communication library written in C. Prior to commit acc03b5, a stack buffer overflow exists in PJSUA when processing Service-Route headers in a registration response (update_service_route() in pjsua_acc.c). This affects applications that register using the PJSUA/PJSUA2 account API (the default registration path). The Service-Route URIs from a 2xx response to REGISTER are stored into a fixed-size array without bounding the number of headers; a registrar that returns an excessive number of Service-Route headers can write past the end of the array on the stack. The values written are internal pointers rather than arbitrary data, so the most likely impact is unexpected application termination (denial of service), though memory corruption cannot be excluded. The malicious response may come from a compromised or malicious registrar, or — over unprotected transports — a spoofed response. This issue has been patched via commit acc03b5.

Scores

EPSS (exploitation in 30 days)

0.46% · top 60% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.

Weakness

• CWE-121: Stack-based Buffer Overflow (opens in a new tab)All about CWE-121 and its CVEs

Affected products

• pjsip · pjproject

  • affected < acc03b57cef7a7d31b8e1f5b9117437d7e87c591

References (2)

• https://github.com/pjsip/pjproject/security/advisories/GHSA-xc62-j9h2-mp84 (opens in a new tab)x_refsource_CONFIRM
• https://github.com/pjsip/pjproject/commit/acc03b57cef7a7d31b8e1f5b9117437d7e87c591 (opens in a new tab)x_refsource_MISC

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-57161](https://trackcve.app/badge/CVE-2026-57161.svg)](https://trackcve.app/cve/CVE-2026-57161)

Record last updated 9 Sept 2026, 17:48 UTC.