# CVE-2026-72761: Server-side request forgery in vulnerability-lookup

> Attackers can bypass SSRF protections using IPv6 transition addresses to access internal endpoints and exfiltrate vulnerability data.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/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:** 10 Aug 2026
- **Updated:** 10 Aug 2026

## What is CVE-2026-72761?

CVE-2026-72761 is a medium-severity server-side request forgery vulnerability in vulnerability-lookup, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The webhook URL validator in `website/notifications/webhooks.py` uses
`ip.is_global` to reject non-public addresses after DNS resolution. IPv6
transition addresses (NAT64 `64:ff9b::/96`, 6to4 `2002::/16`, Teredo
`2001:0000::/32`) are classified as globally routable by IANA, so `is_global`
returns `True` even when the embedded IPv4 targets a private, loopback, or
cloud metadata destination. An attacker can register a webhook pointing at a
hostname that resolves to a transition address to bypass the SSRF guard and
exfiltrate vulnerability data to an internal endpoint.

The vulnerability was introduced on a non-release version. The fix was already done on HEAD. It only affects

organisation running the HEAD.

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

## Which versions are affected by CVE-2026-72761?


## How do I fix CVE-2026-72761?

No fix has been published for CVE-2026-72761 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-72761 being exploited?

There is no known exploitation of CVE-2026-72761 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72761 and fix it if it is affected.

What it is: CVE-2026-72761 is a medium-severity server-side request forgery vulnerability in vulnerability-lookup, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72761 in the wild and no public exploit code.

Affected product: vulnerability-lookup. 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-2026-72761/ (Markdown: https://insights.sbomify.com/CVE-2026-72761/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72761
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72761
- OSV: https://osv.dev/vulnerability/CVE-2026-72761

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72761/
Summaries are generated and may contain mistakes; the official description above is the record.