# CVE-2021-21148: Google Chromium V8 Heap Buffer Overflow

> Remote attackers can execute arbitrary code via heap corruption in V8 by tricking users into visiting a crafted HTML page.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 3 Nov 2021 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 9 Feb 2021
- **Updated:** 21 Oct 2025
- **Also known as:** ALPINE-CVE-2021-21148, CLEANSTART-2026-NN99657, CLEANSTART-2026-RL59134, DEBIAN-CVE-2021-21148, GHSA-6675-f3rx-hqr9, UBUNTU-CVE-2021-21148, openSUSE-SU-2021:0267-1, openSUSE-SU-2021:0276-1, openSUSE-SU-2021:0296-1

## What is CVE-2021-21148?

CVE-2021-21148 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 9 Feb 2021. 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

Heap buffer overflow in V8 in Google Chrome prior to 88.0.4324.150 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-21148?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `chromium` | SUSE:Package Hub 15 SP2 | All versions | 88.0.4324.150-bp152.2.59.1 |
| `chromium` | openSUSE:Leap 15.2 | All versions | 88.0.4324.150-lp152.2.72.1 |
| `opera` | openSUSE:Leap 15.2 NonFree | All versions | 74.0.3911.107-lp152.2.34.1 |

Products: Debian Debian Linux, Fedoraproject Fedora, Google Chrome.

## How do I fix CVE-2021-21148?

Upgrade to a fixed version. US federal agencies must fix it by 17 Nov 2021.

## Is CVE-2021-21148 being exploited?

Yes. Attackers have exploited CVE-2021-21148 in the wild since at least 3 Nov 2021.

Public exploit code:

- https://github.com/Grayhaxor/CVE-2021-21148 (github_poc): https://github.com/Grayhaxor/CVE-2021-21148

## 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-2021-21148 and fix it if it is affected.

What it is: CVE-2021-21148 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 9 Feb 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: Yes. Attackers have exploited CVE-2021-21148 in the wild since at least 3 Nov 2021.

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-2021-21148/ (Markdown: https://insights.sbomify.com/CVE-2021-21148/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21148
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21148
- OSV: https://osv.dev/vulnerability/CVE-2021-21148

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21148/
Summaries are generated and may contain mistakes; the official description above is the record.