# CVE-2026-5204: Tenda CH22 Parameter webtypelibrary formWebTypeLibrary stack-based overflow

> Remote attackers can trigger a stack-based buffer overflow in the Tenda CH22 router's web type library handler, potentially leading to code execution or service disruption.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 31 Mar 2026
- **Updated:** 31 Mar 2026
- **Also known as:** GHSA-5qj8-jcmc-3p6q

## What is CVE-2026-5204?

CVE-2026-5204 is a high-severity memory corruption vulnerability in Tenda CH22, published on 31 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was determined in Tenda CH22 1.0.0.1. Affected is the function formWebTypeLibrary of the file /goform/webtypelibrary of the component Parameter Handler. This manipulation of the argument webSiteId causes stack-based buffer overflow. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized.

Weakness: CWE-121 (Stack-based Buffer Overflow), CWE-787 (Out-of-bounds Write), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-5204?

It affects 1 product.


Products: Tenda Ch22 Firmware.

## How do I fix CVE-2026-5204?

No fix has been published for CVE-2026-5204 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-5204 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-5204 exists.

## Other vulnerabilities in Tenda CH22

- [CVE-2025-11418](https://insights.sbomify.com/CVE-2025-11418/): Tenda CH22 HTTP Request AdvSetWrlsafeset formWrlsafeset stack-based overflow (critical 9.3)
- [CVE-2025-11423](https://insights.sbomify.com/CVE-2025-11423/): Tenda CH22 SafeEmailFilter formSafeEmailFilter memory corruption (critical 9.3)
- [CVE-2026-5604](https://insights.sbomify.com/CVE-2026-5604/): Tenda CH22 Parameter CertLocalPrecreate formCertLocalPrecreate stack-based overflow (high 8.7)
- [CVE-2026-5605](https://insights.sbomify.com/CVE-2026-5605/): Tenda CH22 WrlExtraSet formWrlExtraSet stack-based overflow (high 8.7)
- [CVE-2026-5152](https://insights.sbomify.com/CVE-2026-5152/): Tenda CH22 createFileName formCreateFileName stack-based overflow (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5204 and fix it if it is affected.

What it is: CVE-2026-5204 is a high-severity memory corruption vulnerability in Tenda CH22, published on 31 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-5204 exists.

Affected product: Tenda CH22. 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-2026-5204/ (Markdown: https://insights.sbomify.com/CVE-2026-5204/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5204
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5204
- OSV: https://osv.dev/vulnerability/CVE-2026-5204

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5204/
Summaries are generated and may contain mistakes; the official description above is the record.