# CVE-2026-55655: Other in Red Hat Enterprise Linux 10

> Local attackers can hijack X11 forwarding via abstract socket pre-binding, compromising confidentiality and allowing session manipulation.

- **Severity:** Medium 5.0 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 23 Jun 2026
- **Updated:** 29 Oct 2026
- **Also known as:** AZL-91197, CLSA-2026-1785143860, CLSA-2026-1785153163, GHSA-wcvf-3x75-j4c6, UBUNTU-CVE-2026-55655

## What is CVE-2026-55655?

CVE-2026-55655 is a medium-severity vulnerability in OpenSSH, published on 23 Jun 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can compromise the confidentiality of forwarded X11 traffic, including sensitive window contents and input, and may allow some manipulation of the forwarded session.

Weakness: CWE-923 (Improper Restriction of Communication Channel to Intended Endpoints)

## Which versions are affected by CVE-2026-55655?

It affects 2 products.


Products: OpenSSH, Redhat Enterprise Linux.

## How do I fix CVE-2026-55655?

Apply the vendor's patch.

## Is CVE-2026-55655 being exploited?

There is no known exploitation of CVE-2026-55655 in the wild and no public exploit code.

## Other vulnerabilities in OpenSSH

- [CVE-2003-0786](https://insights.sbomify.com/CVE-2003-0786/): Auth bypass in n/a (critical 10.0)
- [CVE-2003-0693](https://insights.sbomify.com/CVE-2003-0693/): Memory corruption in n/a (critical 10.0)
- [CVE-2002-0640](https://insights.sbomify.com/CVE-2002-0640/): Memory corruption in n/a (critical 10.0)
- [CVE-2001-0144](https://insights.sbomify.com/CVE-2001-0144/): Integer overflow in n/a (critical 10.0)
- [CVE-2000-0999](https://insights.sbomify.com/CVE-2000-0999/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55655 and fix it if it is affected.

What it is: CVE-2026-55655 is a medium-severity vulnerability in OpenSSH, published on 23 Jun 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-55655 in the wild and no public exploit code.

Affected product: OpenSSH. 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-2026-55655/ (Markdown: https://insights.sbomify.com/CVE-2026-55655/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55655
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55655
- OSV: https://osv.dev/vulnerability/CVE-2026-55655

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55655/
Summaries are generated and may contain mistakes; the official description above is the record.