# CVE-2026-55758: CC: Tweaked: Incomplete fix for GHSA-5jh9-2h63-pw4q: RFC 8215 NAT64 prefix (64:ff9b:1::/96) bypasses SSRF protection

> An attacker with Lua execution rights can bypass SSRF protections to access internal network resources via NAT64 prefixes.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/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:** 27 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** GHSA-2rrx-mch2-76cp

## What is CVE-2026-55758?

CVE-2026-55758 is a medium-severity server-side request forgery vulnerability in CC-Tweaked, published on 27 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

CC: Tweaked is a mod for Minecraft which adds programmable computers, turtles, and more to the game. Prior to 1.120.0, the SSRF protection in projects/core/src/main/java/dan200/computercraft/core/apis/http/options/AddressPredicate.java blocks the RFC 6052 64:ff9b::/96 NAT64 prefix but omits the RFC 8215 64:ff9b:1::/48 local-use prefix. On a dual-stack server using RFC 8215 NAT64, an unauthenticated user who can execute Lua code can use http.request or http.websocket with an address under 64:ff9b:1::/48 to reach loopback, RFC 1918, cloud metadata, or internal API endpoints because PrivatePattern.matches() does not classify the mapped IPv6 address as private. This issue is fixed in version 1.120.0.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-55758?


## How do I fix CVE-2026-55758?

No fix has been published for CVE-2026-55758 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-55758 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55758 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55758 and fix it if it is affected.

What it is: CVE-2026-55758 is a medium-severity server-side request forgery vulnerability in CC-Tweaked, published on 27 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-2026-55758 exists.

Affected product: CC-Tweaked. 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-2026-55758/ (Markdown: https://insights.sbomify.com/CVE-2026-55758/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55758
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55758
- OSV: https://osv.dev/vulnerability/CVE-2026-55758

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-55758/
Summaries are generated and may contain mistakes; the official description above is the record.