# CVE-2026-47241: Net::IMAP: Denial of Service via incomplete raw argument validation

> Attackers can cause a denial of service in Ruby's Net::IMAP library by sending crafted raw arguments that block command execution.

- **Severity:** Low 2.1 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 22 Jun 2026
- **Updated:** 23 Jun 2026
- **Also known as:** ALPINE-CVE-2026-47241, BELL-CVE-2026-47241, CLEANSTART-2026-HQ73324, CLEANSTART-2026-NQ87624, DEBIAN-CVE-2026-47241, ECHO-bf99-96ee-af6b, GHSA-c4fp-cxrr-mj66, MINI-22v4-4354-vvmh, MINI-2528-pgg6-h4wp, MINI-2vf5-v3cj-mwcc, MINI-2xhf-q398-q93x, MINI-35f4-gw8q-p3rm, MINI-5pc8-mvx4-vvv3, MINI-7j24-3v7w-qhmm, MINI-7px6-fx4c-7f32, MINI-g4vq-x5w2-66p9, MINI-hww9-r2jp-9c2r, MINI-jq65-38wf-qm57, MINI-r6pm-ccqm-647f, MINI-v2g8-5phm-c9q7, MINI-w8mm-h7mc-m5c5, MINI-xw8g-7x5f-5wrq, UBUNTU-CVE-2026-47241

## What is CVE-2026-47241?

CVE-2026-47241 is a low-severity denial of service vulnerability in ruby net-imap, published on 22 Jun 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, several Net::IMAP commands accept a raw string argument which is only validated to prevent CRLF injection and then sent verbatim. If this string is derived from user-controlled input, an attacker can force the next command to be absorbed as a continuation of the first command. This will cause the first command to eventually fail, but also prevents it from returning until another command is sent (from another thread). That other command will not return until the connection is closed. This vulnerability is fixed in 0.6.5 and 0.5.15.

Weakness: CWE-186 (Overly Restrictive Regular Expression), CWE-182 (Collapse of Data into Unsafe Value), CWE-162 (Improper Neutralization of Trailing Special Elements)

## Which versions are affected by CVE-2026-47241?

4 open source packages ship an affected version, including net-imap.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `net-imap` | RubyGems | All versions | 0.5.15 |
| `net-imap` | RubyGems | All versions | 0.5.15 |
| `net-imap` | RubyGems | From 0.6.0 | 0.6.4.1 |
| `net-imap` | RubyGems | From 0.6.0 | 0.6.4.1 |

## How do I fix CVE-2026-47241?

Upgrade net-imap to a fixed version for your release line: 0.5.15 or 0.6.4.1.

## Is CVE-2026-47241 being exploited?

There is no known exploitation of CVE-2026-47241 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-47241 and fix it if it is affected.

What it is: CVE-2026-47241 is a low-severity denial of service vulnerability in ruby net-imap, published on 22 Jun 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-47241 in the wild and no public exploit code.

Affected packages and fixed versions:
- net-imap (RubyGems): affected all versions; fixed in 0.5.15
- net-imap (RubyGems): affected all versions; fixed in 0.5.15
- net-imap (RubyGems): affected from 0.6.0; fixed in 0.6.4.1
- net-imap (RubyGems): affected from 0.6.0; fixed in 0.6.4.1

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-2026-47241/ (Markdown: https://insights.sbomify.com/CVE-2026-47241/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-47241
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-47241
- OSV: https://osv.dev/vulnerability/CVE-2026-47241

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-47241/
Summaries are generated and may contain mistakes; the official description above is the record.