# CVE-2021-27085: Microsoft Internet Explorer Remote Code Execution

> Attackers can execute arbitrary code on systems using Internet Explorer, requiring users to apply Microsoft security patches.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L/E:P/RL:O/RC:C`)
- **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:** No
- **Published:** 11 Mar 2021
- **Updated:** 19 Aug 2026
- **Also known as:** GHSA-vm76-5x29-7jx8

## What is CVE-2021-27085?

CVE-2021-27085 is a high-severity code injection vulnerability in Microsoft Internet Explorer, published on 11 Mar 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

Internet Explorer Remote Code Execution Vulnerability

## Which versions are affected by CVE-2021-27085?

It affects 1 product.


Products: Microsoft Internet Explorer.

## How do I fix CVE-2021-27085?

No fix has been published for CVE-2021-27085 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 17 Nov 2021.

## Is CVE-2021-27085 being exploited?

Yes. Attackers have exploited CVE-2021-27085 in the wild since at least 3 Nov 2021.

## Other vulnerabilities in Microsoft Internet Explorer

- [CVE-2014-1776](https://insights.sbomify.com/CVE-2014-1776/): Microsoft Internet Explorer Memory Corruption (critical 9.8, exploited in the wild)
- [CVE-2017-0222](https://insights.sbomify.com/CVE-2017-0222/): Microsoft Internet Explorer Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2017-0210](https://insights.sbomify.com/CVE-2017-0210/): Microsoft Internet Explorer Privilege Escalation (high 8.8, exploited in the wild)
- [CVE-2017-0149](https://insights.sbomify.com/CVE-2017-0149/): Microsoft Internet Explorer Memory Corruption (high 8.8, exploited in the wild)
- [CVE-2015-2502](https://insights.sbomify.com/CVE-2015-2502/): Microsoft Internet Explorer Memory Corruption (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27085 and fix it if it is affected.

What it is: CVE-2021-27085 is a high-severity code injection vulnerability in Microsoft Internet Explorer, published on 11 Mar 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-2021-27085 in the wild since at least 3 Nov 2021.

Affected product: Microsoft Internet Explorer. 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-2021-27085/ (Markdown: https://insights.sbomify.com/CVE-2021-27085/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27085
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27085
- OSV: https://osv.dev/vulnerability/CVE-2021-27085

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-27085/
Summaries are generated and may contain mistakes; the official description above is the record.