# CVE-2026-100676: stoatchat before 0.15.5 Local Filesystem Read via SVG

> Unauthenticated attackers can read local files and cause denial of service via malicious SVGs in stoatchat's media proxy service.

- **Severity:** High 8.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/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:** No
- **Published:** 26 Sep 2026
- **Updated:** 28 Sep 2026
- **Also known as:** GHSA-4h96-wm2q-h7fw, GHSA-qv38-hwhv-jm49

## What is CVE-2026-100676?

CVE-2026-100676 is a high-severity path traversal vulnerability in stoatchat, published on 26 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

January, the media proxy/embed service of stoatchat (stoatchat/stoatchat), before version 0.15.5 improperly resolves SVG <image href> values as local filesystem paths when a fetched resource is served as image/svg+xml. An unauthenticated remote attacker who causes the service to proxy an attacker-hosted SVG (e.g. via the /proxy endpoint) can determine whether local files exist through observable response-time differences, and can cause supported local image files to be disclosed after re-encoding. Because each referenced file is read in full with no effective limit on the number or total volume of reads, a single request can also generate an unbounded amount of local filesystem I/O and memory pressure (the published proof of concept drives about 4.34 GB of reads), leading to denial of service. The issue is fixed in 0.15.5.

Weakness: CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-100676?


## How do I fix CVE-2026-100676?

No fix has been published for CVE-2026-100676 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-100676 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100676 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-100676 and fix it if it is affected.

What it is: CVE-2026-100676 is a high-severity path traversal vulnerability in stoatchat, published on 26 Sep 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-2026-100676 exists.

Affected product: stoatchat. 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-2026-100676/ (Markdown: https://insights.sbomify.com/CVE-2026-100676/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-100676
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-100676
- OSV: https://osv.dev/vulnerability/CVE-2026-100676

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-100676/
Summaries are generated and may contain mistakes; the official description above is the record.