# CVE-2021-26620: IPTIME NAS2dual improper authentication vulnerability

> Remote attackers can bypass authentication to steal information and change user passwords on iptime NAS devices.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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:** 25 Mar 2022
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-cc72-grgq-wvmx

## What is CVE-2021-26620?

CVE-2021-26620 is a high-severity authentication bypass vulnerability in EFM Networks Co., Ltd ipTIME NAS product (NAS1, 2, 3, 4, 1dual, 2dual 4dual), published on 25 Mar 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An improper authentication vulnerability leading to information leakage was discovered in iptime NAS2dual. Remote attackers are able to steal important information in the server by exploiting vulnerabilities such as insufficient authentication when accessing the shared folder and changing user’s passwords.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2021-26620?

It affects 9 products.


Products: Iptime Nas-I Firmware, Iptime Nas-Ii Firmware, Iptime Nas-Iie Firmware, Iptime Nas101 Firmware, Iptime Nas1dual Firmware, Iptime Nas2dual Firmware, Iptime Nas3 Firmware, Iptime Nas4 Firmware, Iptime Nas4dual Firmware.

## How do I fix CVE-2021-26620?

No fix has been published for CVE-2021-26620 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-26620 being exploited?

There is no known exploitation of CVE-2021-26620 in the wild and no public exploit code.

## Other vulnerabilities in EFM Networks Co., Ltd ipTIME NAS product (NAS1, 2, 3, 4, 1dual, 2dual 4dual)

- [CVE-2020-7847](https://insights.sbomify.com/CVE-2020-7847/): File upload in ipTIME NAS (high 7.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26620 and fix it if it is affected.

What it is: CVE-2021-26620 is a high-severity authentication bypass vulnerability in EFM Networks Co., Ltd ipTIME NAS product (NAS1, 2, 3, 4, 1dual, 2dual 4dual), published on 25 Mar 2022. 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-2021-26620 in the wild and no public exploit code.

Affected product: EFM Networks Co., Ltd ipTIME NAS product (NAS1, 2, 3, 4, 1dual, 2dual 4dual). 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-2021-26620/ (Markdown: https://insights.sbomify.com/CVE-2021-26620/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26620
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26620
- OSV: https://osv.dev/vulnerability/CVE-2021-26620

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-26620/
Summaries are generated and may contain mistakes; the official description above is the record.