CVE-2026-84975: Cert Validation Flaw (CVSS 7.4)

Description

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.

Is your site exposed to CVE-2026-84975?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.4

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0023

Probability of exploitation

0.13%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-295 CWE-295

CWE-297 CWE-297

References

Other References

https://github.com/pjsip/pjproject/commit/43d3bd77bb6833eab4c493503b8d564a754ddfdd https://github.com/pjsip/pjproject/security/advisories/GHSA-382p-87mh-r3q8

Frequently Asked Questions

What is CVE-2026-84975? +

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. It has a CVSS v3.1 base score of 7.4 (HIGH).

How severe is CVE-2026-84975? +

CVE-2026-84975 has a CVSS v3.1 score of 7.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0023, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-84975? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-44700

Elixir WebRTC is an Elixir implementation of the W3C WebRTC API. Prior to 0.15.1 and 0.16.1, missing DTLS peer certificate …

CVE-2025-9291

A certification validation weakness exists in communication between affected Omada devices and cloud controllers. Certificate identity verification does not adequately …

CVE-2026-0277

An improper certificate validation vulnerability in the Prisma® Access Agent for iOS enables an attacker to perform a man-in-the-middle (MitM) …

CVE-2025-3463

"This issue is limited to motherboards and does not affect laptops, desktop computers, or other endpoints." An insufficient validation vulnerability …

CVE-2025-5279

When the Amazon Redshift Python Connector is configured with the BrowserAzureOAuth2CredentialsProvider plugin, the driver skips the SSL certificate validation step …

CVE-2025-34066

An improper certificate validation vulnerability exists in AVTECH IP cameras, DVRs, and NVRs due to the use of wget with …

CVE-2026-84975