CVE-2026-84975
HighCVSS 7.4Exploitation Probability (EPSS)
Low risk12th percentile - higher than 12% of all known CVEs
Summary
PJSIP is a free and open source multimedia communication library written in C. In 2.17 and earlier, the OpenSSL and GnuTLS backends copy DNS SubjectAltName values with string functions that recalculate their length and truncate an embedded NUL byte. With server verification enabled through --tls-verify-server, a certificate containing a DNS SubjectAltName formed from the target hostname prefix followed by an embedded NUL and an attacker-controlled suffix can be accepted for the prefix hostname.
Risk Assessment
An attacker with a certificate from a trusted issuer who can intercept the connection can impersonate the target server, complete the SIP session, and receive REGISTER credentials. This leads to account takeover and breach of communication confidentiality.
Recommendation
No fixed version is available — monitor PJSIP updates and consider using the mbedTLS backend, which is not affected. Until a patch is released, apply additional protections for TLS/SIPS connections.
Other vulnerabilities in PJSIP
See all- CVE-2022-24763High
PJSIP is a free and open source multimedia communication library written in the C language. Versions 2.12 and prior contain a denial-of-service vulnerability that affects PJSIP users that consume PJSIP's XML parsing in their apps.
- CVE-2026-57163Critical
PJSIP prior to commit c4a151a has a stack buffer overflow in the GnuTLS TLS backend when parsing the Subject Alternative Name extension of a peer certificate. An incorrect buffer-size value can cause an oversized entry to be written past the end of a fixed-size stack buffer.
- CVE-2026-57162Critical
PJSIP prior to commit a1b707c has a stack buffer overflow in the SRTP/SDES media transport when processing a=crypto attributes during SDP offer/answer. An excessive number of attributes can cause a write past the end of a fixed-size array on the stack.
- CVE-2026-34235Critical
PJSIP before version 2.17 has a heap out-of-bounds read vulnerability in the VP9 RTP unpacketizer. Insufficient bounds checking on payload descriptor length may cause reads beyond the allocated RTP buffer.
- CVE-2022-39269Critical
PJSIP is a free and open source multimedia communication library that may incorrectly switch from using SRTP media transport to basic RTP upon SRTP restart. This leads to media being sent insecurely.
- CVE-2026-77396Medium
PJSIP is a free and open source multimedia communication library written in C. In 2.17 and earlier, the PJSIP AVI parser in pjmedia/src/pjmedia/avi_player.c uses an input-file video chunk length as the number of bytes copied into a frame buffer whose capacity is derived from the declared media dimensions. A crafted AVI file can therefore cause an attacker-controlled out-of-bounds write past the heap allocation when an application plays the file or pulls its frames. The existing size assertion does not protect production release builds, where assertions are disabled. Typical local playback can crash the process, while applications that accept untrusted AVI sources expose a stronger memory-corruption condition. No fixed version is available as of this review.
- CVE-2026-57166Medium
PJSIP before commit 4472a31 has a stack buffer overflow in the PJLIB-UTIL telnet CLI front-end when rendering feedback for an entered command line. An overly long command line can overflow fixed-size buffers, potentially causing application termination. Only applications with the telnet CLI front-end enabled are affected.
- CVE-2026-57165Medium
In the PJSIP library before commit 628b716, there is a stack buffer overflow in the telnet CLI front-end (handle_up_down() in cli_telnet.c) when redrawing the command line during history recall. This affects only applications with the telnet CLI enabled and may lead to application termination. Exploitation requires access to the unauthenticated telnet CLI, which already permits arbitrary CLI commands, so the additional impact is limited.
- CVE-2026-57164Medium
PJSIP prior to commit 8d5956a has a heap buffer overflow in the PJLIB-UTIL HTTP client when buffering an HTTP response body. An incorrect size calculation based on Content-Length can cause data to be written past the end of the buffer.
- CVE-2026-57161High
PJSIP prior to commit acc03b5 has a stack buffer overflow in PJSUA when processing Service-Route headers in a registration response. An excessive number of headers can cause a write past the end of a fixed-size array on the stack.
Original NVD description (English source)
PJSIP is a free and open source multimedia communication library written in C. In 2.17 and earlier, the OpenSSL and GnuTLS backends in pjlib/src/pj/ssl_sock_ossl.c and pjlib/src/pj/ssl_sock_gtls.c copy DNS SubjectAltName values with string functions that recalculate their length and truncate an embedded NUL byte. With server verification enabled through --tls-verify-server for the PJSIP TLS/SIPS transport, a certificate containing a DNS SubjectAltName formed from the target hostname prefix followed by an embedded NUL and an attacker-controlled suffix can therefore be accepted for the prefix hostname. An attacker who possesses such a certificate from a trusted issuer and can intercept the connection can impersonate the target server, complete the SIP session, and receive REGISTER credentials. The mbedTLS backend is not affected because it preserves the explicit string length. No fixed version is available as of this review.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

