# CVE-2026-77946: TRENDnet TEW-821DAP NTP Timezone Configuration apply_time.cgi uci_safe_get stack-based overflow

> Remote attackers can trigger a stack-based buffer overflow in the NTP timezone configuration handler, potentially leading to arbitrary code execution on the device.

- **Severity:** Critical 10.0 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Aug 2026
- **Updated:** 26 Aug 2026
- **Also known as:** GHSA-cvhx-h689-9gjx

## What is CVE-2026-77946?

CVE-2026-77946 is a critical memory corruption vulnerability in TRENDnet TEW-821DAP, published on 22 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was determined in TRENDnet TEW-821DAP 2.2.01b05. Affected by this vulnerability is the function uci_safe_get of the file /cgi-bin/apply_time.cgi of the component NTP Timezone Configuration Handler. Executing a manipulation of the argument system.ntp.server/system.ntp.enable_server/cameo.time.time_zone/cameo.cameo.syslog_server can lead to stack-based buffer overflow. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized.

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

## Which versions are affected by CVE-2026-77946?


## How do I fix CVE-2026-77946?

No fix has been published for CVE-2026-77946 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-77946 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-77946 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77946 and fix it if it is affected.

What it is: CVE-2026-77946 is a critical memory corruption vulnerability in TRENDnet TEW-821DAP, published on 22 Aug 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-2026-77946 exists.

Affected product: TRENDnet TEW-821DAP. 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-2026-77946/ (Markdown: https://insights.sbomify.com/CVE-2026-77946/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77946
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77946
- OSV: https://osv.dev/vulnerability/CVE-2026-77946

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-77946/
Summaries are generated and may contain mistakes; the official description above is the record.