# CVE-2021-41349: Microsoft Exchange Server Spoofing Vulnerability

> An attacker can spoof email headers in Microsoft Exchange Server, bypassing security controls and misleading recipients.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 10 Nov 2021
- **Updated:** 19 Aug 2026
- **Also known as:** GHSA-xjg9-924r-39mj

## What is CVE-2021-41349?

CVE-2021-41349 is a medium-severity vulnerability in Microsoft Exchange Server, published on 10 Nov 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

Microsoft Exchange Server Spoofing Vulnerability

## Which versions are affected by CVE-2021-41349?

It affects 1 product.


Products: Microsoft Exchange Server.

## How do I fix CVE-2021-41349?

No fix has been published for CVE-2021-41349 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-41349 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-41349 exists.

Public exploit code:

- Exploiting: CVE-2021-41349 (github_poc): https://github.com/exploit-io/CVE-2021-41349
- Microsoft Exchange Server Spoofing Vulnerability Exploit! (github_poc): https://github.com/0xrobiul/CVE-2021-41349
- Microsoft Exchange Server Pre-Auth POST Based Cross-Site Scripting (nuclei): http/cves/2021/CVE-2021-41349.yaml

## Other vulnerabilities in Microsoft Exchange Server

- [CVE-2024-21410](https://insights.sbomify.com/CVE-2024-21410/): Microsoft Exchange Server Privilege Escalation (critical 9.8, exploited in the wild)
- [CVE-2021-34473](https://insights.sbomify.com/CVE-2021-34473/): Microsoft Exchange Server Remote Code Execution (critical 9.1, exploited in the wild)
- [CVE-2021-26855](https://insights.sbomify.com/CVE-2021-26855/): Microsoft Exchange Server Remote Code Execution (critical 9.1, exploited in the wild)
- [CVE-2021-34523](https://insights.sbomify.com/CVE-2021-34523/): Microsoft Exchange Server Privilege Escalation (critical 9.0, exploited in the wild)
- [CVE-2023-21529](https://insights.sbomify.com/CVE-2023-21529/): Microsoft Exchange Server Deserialization of Untrusted Data (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41349 and fix it if it is affected.

What it is: CVE-2021-41349 is a medium-severity vulnerability in Microsoft Exchange Server, published on 10 Nov 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-41349 exists.

Affected product: Microsoft Exchange Server. 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-2021-41349/ (Markdown: https://insights.sbomify.com/CVE-2021-41349/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41349
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41349
- OSV: https://osv.dev/vulnerability/CVE-2021-41349

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41349/
Summaries are generated and may contain mistakes; the official description above is the record.