# CVE-2026-15544: Shibby Tomato apcupsd tomatodata.cgi getupsvar stack-based overflow

> Remote attackers can trigger a stack-based buffer overflow in the apcupsd component of Shibby Tomato firmware to execute arbitrary code.

- **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:** 13 Jul 2026
- **Updated:** 13 Jul 2026
- **Also known as:** GHSA-hp2q-5cpp-5m3x

## What is CVE-2026-15544?

CVE-2026-15544 is a high-severity memory corruption vulnerability in Shibby Tomato, published on 13 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was determined in Shibby Tomato up to 1.28.0000. Affected is the function getupsvar of the file www/apcupsd/tomatodata.cgi of the component apcupsd. This manipulation of the argument Field causes stack-based buffer overflow. The attack may be initiated remotely. The exploit has been publicly disclosed and may be utilized. This project is superseded by FreshTomato.

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-2026-15544?


## How do I fix CVE-2026-15544?

No fix has been published for CVE-2026-15544 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-15544 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-15544 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-15544 and fix it if it is affected.

What it is: CVE-2026-15544 is a high-severity memory corruption vulnerability in Shibby Tomato, published on 13 Jul 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-2026-15544 exists.

Affected product: Shibby Tomato. 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-2026-15544/ (Markdown: https://insights.sbomify.com/CVE-2026-15544/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-15544
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-15544
- OSV: https://osv.dev/vulnerability/CVE-2026-15544

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-15544/
Summaries are generated and may contain mistakes; the official description above is the record.