# CVE-2021-37845: Security feature bypass in n/a

> A man-in-the-middle attacker can hijack sessions during the cleartext phase before STARTTLS, potentially redirecting victim emails to the attacker's mailbox.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 May 2023
- **Updated:** 14 Jan 2025
- **Also known as:** GHSA-hh3j-j42w-mrpm, UBUNTU-CVE-2021-37845

## What is CVE-2021-37845?

CVE-2021-37845 is a low-severity vulnerability in n/a, published on 29 May 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle attacker can fixate their own session during the cleartext phase before a STARTTLS command (a violation of "The STARTTLS command is only valid in non-authenticated state." in RFC2595). This potentially allows an attacker to cause a victim's e-mail messages to be stored into an attacker's IMAP mailbox, but depends on details of the victim's client behavior.

## Which versions are affected by CVE-2021-37845?

It affects 1 product.


Products: Citadel Webcit.

## How do I fix CVE-2021-37845?

No fix has been published for CVE-2021-37845 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-37845 being exploited?

There is no known exploitation of CVE-2021-37845 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2020-27739](https://insights.sbomify.com/CVE-2020-27739/): Auth bypass in n/a (critical 9.8)
- [CVE-2009-0364](https://insights.sbomify.com/CVE-2009-0364/): Other in n/a (high 7.5)
- [CVE-2007-3821](https://insights.sbomify.com/CVE-2007-3821/): Cross-site request forgery in n/a (high 7.5)
- [CVE-2020-27742](https://insights.sbomify.com/CVE-2020-27742/): Information disclosure in n/a (medium 6.5)
- [CVE-2020-27741](https://insights.sbomify.com/CVE-2020-27741/): Cross-site scripting in n/a (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-37845 and fix it if it is affected.

What it is: CVE-2021-37845 is a low-severity vulnerability in n/a, published on 29 May 2023. 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-2021-37845 in the wild and no public exploit code.

Affected product: n/a. 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-2021-37845/ (Markdown: https://insights.sbomify.com/CVE-2021-37845/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-37845
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-37845
- OSV: https://osv.dev/vulnerability/CVE-2021-37845

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-37845/
Summaries are generated and may contain mistakes; the official description above is the record.