# CVE-2021-3772: Denial of service in kernel

> A blind attacker can terminate existing SCTP associations by sending invalid chunks with spoofed IP addresses, causing a denial of service.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Mar 2022
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-3772, GHSA-g6gr-2x73-gj6f, UBUNTU-CVE-2021-3772

## What is CVE-2021-3772?

CVE-2021-3772 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 2 Mar 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in the Linux SCTP stack. A blind attacker may be able to kill an existing SCTP association through invalid chunks if the attacker knows the IP-addresses and port numbers being used and the attacker can send packets with spoofed IP addresses.

Weakness: CWE-354 (Improper Validation of Integrity Check Value)

## Which versions are affected by CVE-2021-3772?

It affects 18 products.


Products: Debian Debian Linux, Linux kernel, Netapp E-Series Santricity Os Controller, Netapp H300s Firmware, Netapp H410c Firmware, Netapp H410s Firmware, Netapp H500s Firmware, Netapp H610c Firmware, Netapp H610s Firmware, Netapp H615c Firmware, Netapp H700s Firmware, Netapp Hci Compute Node, Netapp Solidfire \& Hci Management Node, Netapp Solidfire \& Hci Storage Node, Oracle Communications Cloud Native Core Binding Support Function, Oracle Communications Cloud Native Core Network Exposure Function, Oracle Communications Cloud Native Core Policy, Redhat Enterprise Linux.

## How do I fix CVE-2021-3772?

Apply the vendor's patch.

## Is CVE-2021-3772 being exploited?

There is no known exploitation of CVE-2021-3772 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3772 and fix it if it is affected.

What it is: CVE-2021-3772 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 2 Mar 2022. 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-2021-3772 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2021-3772/ (Markdown: https://insights.sbomify.com/CVE-2021-3772/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3772
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3772
- OSV: https://osv.dev/vulnerability/CVE-2021-3772

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3772/
Summaries are generated and may contain mistakes; the official description above is the record.