# CVE-2025-40911: Security feature bypass in Net::CIDR::Set

> Attackers can bypass IP-based access controls by using leading zeros in CIDR strings, affecting Perl applications using Net::CIDR::Set.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 May 2025
- **Updated:** 28 May 2025
- **Also known as:** DEBIAN-CVE-2025-40911, GHSA-p745-hrr6-rg8c, UBUNTU-CVE-2025-40911

## What is CVE-2025-40911?

CVE-2025-40911 is a medium-severity vulnerability in RRWO Net::CIDR::Set, published on 27 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Net::CIDR::Set versions 0.10 through 0.13 for Perl does not properly handle leading zero characters in IP CIDR address strings, which could allow attackers to bypass access control that is based on IP addresses.

Leading zeros are used to indicate octal numbers, which can confuse users who are intentionally using octal notation, as well as users who believe they are using decimal notation.

Net::CIDR::Set used code from Net::CIDR::Lite, which had a similar vulnerability CVE-2021-47154.

Weakness: CWE-1287 (Improper Validation of Specified Type of Input)

## Which versions are affected by CVE-2025-40911?


## How do I fix CVE-2025-40911?

Apply the vendor's patch.

## Is CVE-2025-40911 being exploited?

There is no known exploitation of CVE-2025-40911 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40911 and fix it if it is affected.

What it is: CVE-2025-40911 is a medium-severity vulnerability in RRWO Net::CIDR::Set, published on 27 May 2025. 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-2025-40911 in the wild and no public exploit code.

Affected product: RRWO Net::CIDR::Set. 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-2025-40911/ (Markdown: https://insights.sbomify.com/CVE-2025-40911/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40911
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40911
- OSV: https://osv.dev/vulnerability/CVE-2025-40911

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-40911/
Summaries are generated and may contain mistakes; the official description above is the record.