# CVE-2020-15260: Existing TLS connections can be reused without checking remote hostname

> PJSIP reuses TLS connections based on IP address without verifying hostnames, enabling man-in-the-middle attacks via DNS spoofing.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/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:** Yes
- **Published:** 10 Mar 2021
- **Updated:** 4 Aug 2024
- **Also known as:** ALPINE-CVE-2020-15260, DEBIAN-CVE-2020-15260, GHSA-8hcp-hm38-mfph, UBUNTU-CVE-2020-15260

## What is CVE-2020-15260?

CVE-2020-15260 is a medium-severity vulnerability in pjsip pjproject, published on 10 Mar 2021. 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 language implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. In version 2.10 and earlier, PJSIP transport can be reused if they have the same IP address + port + protocol. However, this is insufficient for secure transport since it lacks remote hostname authentication. Suppose we have created a TLS connection to `sip.foo.com`, which has an IP address `100.1.1.1`. If we want to create a TLS connection to another hostname, say `sip.bar.com`, which has the same IP address, then it will reuse that existing connection, even though `100.1.1.1` does not have certificate to authenticate as `sip.bar.com`. The vulnerability allows for an insecure interaction without user awareness. It affects users who need access to connections to different destinations that translate to the same address, and allows man-in-the-middle attack if attacker can route a connection to another destination such as in the case of DNS spoofing.

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

## Which versions are affected by CVE-2020-15260?

It affects 1 product.


Products: Teluu Pjsip.

## How do I fix CVE-2020-15260?

Apply the vendor's patch.

## Is CVE-2020-15260 being exploited?

There is no known exploitation of CVE-2020-15260 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-2020-15260 and fix it if it is affected.

What it is: CVE-2020-15260 is a medium-severity vulnerability in pjsip pjproject, published on 10 Mar 2021. 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-2020-15260 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-2020-15260/ (Markdown: https://insights.sbomify.com/CVE-2020-15260/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-15260
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-15260
- OSV: https://osv.dev/vulnerability/CVE-2020-15260

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-15260/
Summaries are generated and may contain mistakes; the official description above is the record.