# CVE-2026-62143: Server-Side Request Forgery protection bypass in misp-modules html_to_markdown via IPv4-mapped IPv6 addresses

> An authenticated attacker can bypass SSRF protections in MISP modules using IPv4-mapped IPv6 addresses to access internal services and metadata.

- **Severity:** High 8.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/AU:Y/RE:M/U:Green`)
- **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:** 14 Jul 2026
- **Also known as:** GHSA-xv9c-v5pw-jxvf

## What is CVE-2026-62143?

CVE-2026-62143 is a high-severity server-side request forgery vulnerability in misp-modules, published on 13 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A Server-Side Request Forgery (SSRF) protection bypass existed in the html_to_markdown expansion module of misp-modules.

The module attempts to prevent requests to loopback, private, link-local, and other restricted IP address ranges. However, IP addresses were compared against the blocked ranges without first normalising IPv4-mapped IPv6 addresses.

An authenticated attacker able to invoke the module could supply an IPv4-mapped IPv6 address, such as:

http://[::ffff:127.0.0.1]/
http://[::ffff:169.254.169.254]/

Alternatively, the attacker could use a hostname that resolves to an IPv4-mapped IPv6 address. These addresses were treated as IPv6 addresses and therefore did not match the corresponding blocked IPv4 ranges.

Successful exploitation could cause the misp-modules server to connect to services available through its loopback interface, internal network, or link-local network. This could expose internal web services, administrative interfaces, or cloud instance metadata, with retrieved content potentially returned to the attacker as converted Markdown.

The vulnerability has been addressed by normalising IPv4-mapped IPv6 addresses to their underlying IPv4 representation before applying the blocked-range checks. URLs without a valid hostname are now also rejected.

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

## Which versions are affected by CVE-2026-62143?


## How do I fix CVE-2026-62143?

No fix has been published for CVE-2026-62143 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-62143 being exploited?

There is no known exploitation of CVE-2026-62143 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-62143 and fix it if it is affected.

What it is: CVE-2026-62143 is a high-severity server-side request forgery vulnerability in misp-modules, published on 13 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-62143 in the wild and no public exploit code.

Affected product: misp-modules. 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-2026-62143/ (Markdown: https://insights.sbomify.com/CVE-2026-62143/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-62143
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62143
- OSV: https://osv.dev/vulnerability/CVE-2026-62143

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-62143/
Summaries are generated and may contain mistakes; the official description above is the record.