# CVE-2026-82309: Robots::Validate versions from 0.3.2 before 0.3.11 for Perl allow unbounded outbound DNS queries per validation via a forward-confirmation l

> Attackers can cause denial of service by triggering unbounded outbound DNS queries via a forward-confirmation loop in the Perl Robots::Validate library.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N`)
- **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:** 4 Sep 2026
- **Updated:** 8 Sep 2026
- **Also known as:** GHSA-6399-5qhh-48h5

## What is CVE-2026-82309?

CVE-2026-82309 is a medium-severity denial of service vulnerability, published on 4 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Robots::Validate versions from 0.3.2 before 0.3.11 for Perl allow unbounded outbound DNS queries per validation via a forward-confirmation loop that does not bound the names it queries.

_check_dns issues one PTR query for the client address, keeps the returned names matching the rule's domain, and issues a forward query for each until one resolves back to that address. Nothing bounds that list, and a client controls the reverse zone for its own address, so it chooses how many names the PTR answer holds. Net::DNS refetches a truncated answer over TCP by default, so the 512-byte UDP payload does not cap it either.

Any client whose User-Agent matches a rule with a domain reaches _check_dns. Each forward name is distinct and client-chosen, so every query misses the local cache and is resolved against the authoritative servers for that domain. The queries are synchronous, so the caller is held until all of them answer or time out.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-405 (Asymmetric Resource Consumption (Amplification))

## Which versions are affected by CVE-2026-82309?


## How do I fix CVE-2026-82309?

No fix has been published for CVE-2026-82309 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-82309 being exploited?

There is no known exploitation of CVE-2026-82309 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82309 and fix it if it is affected.

What it is: CVE-2026-82309 is a medium-severity denial of service vulnerability, published on 4 Sep 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-2026-82309 in the wild and no public exploit code.

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-2026-82309/ (Markdown: https://insights.sbomify.com/CVE-2026-82309/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82309
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82309
- OSV: https://osv.dev/vulnerability/CVE-2026-82309

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-82309/
Summaries are generated and may contain mistakes; the official description above is the record.