# CVE-2026-32854: LibVNCServer httpd proxy NULL Pointer Dereference

> Remote attackers can crash the LibVNCServer by sending crafted HTTP requests when proxy features are enabled, causing a denial of service.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Mar 2026
- **Updated:** 14 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-32854, GHSA-xjp8-4qqv-5x4x, UBUNTU-CVE-2026-32854

## What is CVE-2026-32854?

CVE-2026-32854 is a medium-severity vulnerability in LibVNCServer, published on 24 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

LibVNCServer versions 0.9.15 and prior (fixed in commit dc78dee) contain null pointer dereference vulnerabilities in the HTTP proxy handlers within httpProcessInput() in httpd.c that allow remote attackers to cause a denial of service by sending specially crafted HTTP requests. Attackers can exploit missing validation of strchr() return values in the CONNECT and GET proxy handling paths to trigger null pointer dereferences and crash the server when httpd and proxy features are enabled.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-32854?

It affects 1 product.


Products: Libvncserver Project Libvncserver.

## How do I fix CVE-2026-32854?

Apply the vendor's patch.

## Is CVE-2026-32854 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32854 exists.

## Other vulnerabilities in LibVNCServer

- [CVE-2016-9941](https://insights.sbomify.com/CVE-2016-9941/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-9942](https://insights.sbomify.com/CVE-2016-9942/): Memory corruption in n/a (critical 9.8)
- [CVE-2026-32853](https://insights.sbomify.com/CVE-2026-32853/): LibVNCServer UltraZip Encoding Heap Out-of-bounds Read (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-32854 and fix it if it is affected.

What it is: CVE-2026-32854 is a medium-severity vulnerability in LibVNCServer, published on 24 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32854 exists.

Affected product: LibVNCServer. 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-2026-32854/ (Markdown: https://insights.sbomify.com/CVE-2026-32854/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-32854
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-32854
- OSV: https://osv.dev/vulnerability/CVE-2026-32854

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-32854/
Summaries are generated and may contain mistakes; the official description above is the record.