# CVE-2025-49177: Xorg-x11-server-xwayland: xorg-x11-server: tigervnc: data leak in xfixes extension's xfixessetclientdisconnectmode

> A flaw in the XFIXES extension allows a client to read unintended memory from previous requests due to missing length validation.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Jun 2025
- **Updated:** 30 Jun 2026
- **Also known as:** AZL-64271, BELL-CVE-2025-49177, DEBIAN-CVE-2025-49177, GHSA-pw35-9xmg-v8xw, UBUNTU-CVE-2025-49177

## What is CVE-2025-49177?

CVE-2025-49177 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 17 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw was found in the XFIXES extension. The XFixesSetClientDisconnectMode handler does not validate the request length, allowing a client to read unintended memory from previous requests.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2025-49177?


## How do I fix CVE-2025-49177?

Apply the vendor's patch.

## Is CVE-2025-49177 being exploited?

There is no known exploitation of CVE-2025-49177 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-49177 and fix it if it is affected.

What it is: CVE-2025-49177 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 17 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-49177 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. 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-2025-49177/ (Markdown: https://insights.sbomify.com/CVE-2025-49177/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-49177
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-49177
- OSV: https://osv.dev/vulnerability/CVE-2025-49177

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-49177/
Summaries are generated and may contain mistakes; the official description above is the record.