# CVE-2021-3326: Denial of service in n/a

> Attackers can cause a denial of service by triggering an assertion failure in glibc's iconv function when processing invalid ISO-2022-JP-3 input.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 27 Jan 2021
- **Updated:** 14 Oct 2026
- **Also known as:** CLSA-2026-1777481470, DEBIAN-CVE-2021-3326, GHSA-w279-vhxx-7qx8, OESA-2021-1045, UBUNTU-CVE-2021-3326

## What is CVE-2021-3326?

CVE-2021-3326 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 27 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The iconv function in the GNU C Library (aka glibc or libc6) 2.32 and earlier, when processing invalid input sequences in the ISO-2022-JP-3 encoding, fails an assertion in the code path and aborts the program, potentially resulting in a denial of service.

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2021-3326?

It affects 11 products.


Products: Debian Debian Linux, Fujitsu M10-1 Firmware, Fujitsu M10-4 Firmware, Fujitsu M10-4s Firmware, Fujitsu M12-1 Firmware, Fujitsu M12-2 Firmware, Fujitsu M12-2s Firmware, Gnu Glibc, Netapp E-Series Santricity Os Controller, Netapp Ontap Select Deploy Administration Utility, Oracle Communications Cloud Native Core Security Edge Protection Proxy.

## How do I fix CVE-2021-3326?

Apply the vendor's patch.

## Is CVE-2021-3326 being exploited?

There is no known exploitation of CVE-2021-3326 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-2021-3326 and fix it if it is affected.

What it is: CVE-2021-3326 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 27 Jan 2021. 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-2021-3326 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-2021-3326/ (Markdown: https://insights.sbomify.com/CVE-2021-3326/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3326
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3326
- OSV: https://osv.dev/vulnerability/CVE-2021-3326

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3326/
Summaries are generated and may contain mistakes; the official description above is the record.