CVE-2026-123959 TOTOLINK CA300-PoE cstecgi.cgi setLanguageCfg buffer overflow
Critical 9.4
Published
Updated
Check this codebase for CVE-2026-123959 and fix it if it is affected.
What it is: CVE-2026-123959 is a critical vulnerability in TOTOLINK CA300-PoE, published on 7 Nov 2026.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-123959 exists.
Affected product: TOTOLINK CA300-PoE. 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-2026-123959/ (Markdown: https://insights.sbomify.com/CVE-2026-123959/index.md)
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-123959?
CVE-2026-123959 is a critical vulnerability in TOTOLINK CA300-PoE, published on 7 Nov 2026.
Official description
A security flaw has been discovered in TOTOLINK CA300-PoE 6.2c.884. The impacted element is the function setLanguageCfg of the file /cgi-bin/cstecgi.cgi. Performing a manipulation of the argument langType results in buffer overflow. The attack can be initiated remotely. The exploit has been released to the public and may be used for attacks.
Which versions are affected by CVE-2026-123959?
How do I fix CVE-2026-123959?
No fix has been published for CVE-2026-123959 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-123959 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-123959 exists.
Sources
Also known as GHSA-8359-43qx-xvjr.