# CVE-2026-84975: Security feature bypass in pjproject

> Attackers can bypass TLS hostname verification in PJSIP to impersonate servers and steal SIP credentials when server verification is enabled.

- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Sep 2026
- **Updated:** 24 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-84975, GHSA-382p-87mh-r3q8, UBUNTU-CVE-2026-84975

## What is CVE-2026-84975?

CVE-2026-84975 is a high-severity vulnerability in pjsip pjproject, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-297 (Improper Validation of Certificate with Host Mismatch), CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-84975?

It affects 1 product.


Products: Teluu Pjsip.

## How do I fix CVE-2026-84975?

No fix has been published for CVE-2026-84975 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-84975 being exploited?

There is no known exploitation of CVE-2026-84975 in the wild and no public exploit code.

## Other vulnerabilities in pjsip pjproject

- [CVE-2023-38703](https://insights.sbomify.com/CVE-2023-38703/): PJSIP has use-after-free vulnerability in SRTP media transport (critical 9.8)
- [CVE-2022-39269](https://insights.sbomify.com/CVE-2022-39269/): Media transport downgrade from the secure version (SRTP) to non-secure (RTP) in pjsip (critical 9.1)
- [CVE-2026-57161](https://insights.sbomify.com/CVE-2026-57161/): PJSIP: Stack overflow handling Service-Route headers in a registration response (high 8.8)
- [CVE-2026-57162](https://insights.sbomify.com/CVE-2026-57162/): PJSIP: Stack overflow parsing SDP a=crypto attributes (high 8.8)
- [CVE-2026-57163](https://insights.sbomify.com/CVE-2026-57163/): PJSIP: Stack overflow parsing a TLS peer certificate's SubjectAltName in GnuTLS backend (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-84975 and fix it if it is affected.

What it is: CVE-2026-84975 is a high-severity vulnerability in pjsip pjproject, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-84975 in the wild and no public exploit code.

Affected product: pjsip pjproject. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-84975/ (Markdown: https://insights.sbomify.com/CVE-2026-84975/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-84975
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-84975
- OSV: https://osv.dev/vulnerability/CVE-2026-84975

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-84975/
Summaries are generated and may contain mistakes; the official description above is the record.