Improper certificate validation in pjsip pjproject
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- Spoofing
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-295.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-84975
References
More pjsip vulnerabilities
- TI-2022-13076 Potential stack buffer overflow when parsing message as a STUN client CVSS 3.1CRITICAL 9.8
- TI-2022-08599 Potential out-of-bound read/write in PJSIP CVSS 3.1CRITICAL 9.8
- TI-2023-20051 PJSIP has use-after-free vulnerability in SRTP media transport CVSS 3.1CRITICAL 9.8
- TI-2022-06096 Out-of-bounds read in multipart parsing in PJSIP CVSS 3.1CRITICAL 9.1
- TI-2022-07661 Use after free in PJSIP CVSS 3.1CRITICAL 9.8
- TI-2022-06095 Potential out-of-bound read during RTP/RTCP parsing in PJSIP CVSS 3.1CRITICAL 9.1
Sources
- CVE-2026-84975 · CVE Program
- CVE-2026-84975 · NVD
- FIRST EPSS
- CVE-2026-84975 · Red Hat security data · CC BY 4.0
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