# CVE-2021-47154: Security feature bypass in n/a

> Attackers can bypass IP-based access controls by using leading zeros in IP addresses, affecting applications using the Perl Net::CIDR::Lite module.

- **Severity:** Medium 6.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 18 Mar 2024
- **Updated:** 15 Nov 2024
- **Also known as:** DEBIAN-CVE-2021-47154, DLA-3770-1, GHSA-gpvh-42rv-p6wg, OESA-2024-1303, OESA-2024-1304, OESA-2024-1305, SUSE-SU-2024:1256-1, UBUNTU-CVE-2021-47154, USN-6712-1

## What is CVE-2021-47154?

CVE-2021-47154 is a medium-severity vulnerability in n/a, published on 18 Mar 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

The Net::CIDR::Lite module before 0.22 for Perl does not properly consider extraneous zero characters at the beginning of an IP address string, which (in some situations) allows attackers to bypass access control that is based on IP addresses.

## Which versions are affected by CVE-2021-47154?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `perl-Net-CIDR-Lite` | SUSE:Linux Enterprise Module for Development Tools 15 SP5 | All versions | 0.21-150100.6.3.1 |
| `perl-Net-CIDR-Lite` | openSUSE:Leap 15.5 | All versions | 0.21-150100.6.3.1 |

## How do I fix CVE-2021-47154?

Upgrade to a fixed version.

## Is CVE-2021-47154 being exploited?

There is no known exploitation of CVE-2021-47154 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47154 and fix it if it is affected.

What it is: CVE-2021-47154 is a medium-severity vulnerability in n/a, published on 18 Mar 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-47154 in the wild and no public exploit code.

Affected product: n/a. 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-2021-47154/ (Markdown: https://insights.sbomify.com/CVE-2021-47154/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47154
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47154
- OSV: https://osv.dev/vulnerability/CVE-2021-47154

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47154/
Summaries are generated and may contain mistakes; the official description above is the record.