# CVE-2021-26928: Missing authorization in n/a

> BIRD lacks BGP peer password authentication, allowing attackers to redirect routes for denial of service or information disclosure.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **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 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-cx5r-6jgc-m635

## What is CVE-2021-26928?

CVE-2021-26928 is a medium-severity missing authorization vulnerability in n/a, published on 4 Jun 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

BIRD through 2.0.7 does not provide functionality for password authentication of BGP peers. Because of this, products that use BIRD (which may, for example, include Tigera products in some configurations, as well as products of other vendors) may have been susceptible to route redirection for Denial of Service and/or Information Disclosure. NOTE: a researcher has asserted that the behavior is within Tigera’s area of responsibility; however, Tigera disagrees

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2021-26928?

It affects 1 product.


Products: Nic Bird.

## How do I fix CVE-2021-26928?

No fix has been published for CVE-2021-26928 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-26928 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-26928 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26928 and fix it if it is affected.

What it is: CVE-2021-26928 is a medium-severity missing authorization vulnerability in n/a, published on 4 Jun 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-26928 exists.

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-2021-26928/ (Markdown: https://insights.sbomify.com/CVE-2021-26928/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26928
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26928
- OSV: https://osv.dev/vulnerability/CVE-2021-26928

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-26928/
Summaries are generated and may contain mistakes; the official description above is the record.