# CVE-2026-4541: janmojzis tinyssh Ed25519 Signature crypto_sign_ed25519_tinyssh.c signature verification

> Attackers can bypass authentication in tinyssh due to improper Ed25519 signature verification, requiring local access and high complexity.

- **Severity:** Low 2.0 (`CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Mar 2026
- **Updated:** 18 Apr 2026
- **Also known as:** DEBIAN-CVE-2026-4541, GHSA-g37f-4r6m-qg8m, UBUNTU-CVE-2026-4541

## What is CVE-2026-4541?

CVE-2026-4541 is a low-severity vulnerability in janmojzis tinyssh, published on 22 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw has been found in janmojzis tinyssh up to 20250501. Impacted is an unknown function of the file tinyssh/crypto_sign_ed25519_tinyssh.c of the component Ed25519 Signature Handler. This manipulation causes improper verification of cryptographic signature. The attack is restricted to local execution. The attack's complexity is rated as high. The exploitability is considered difficult. The exploit has been published and may be used. Upgrading to version 20260301 is recommended to address this issue. Patch name: 9c87269607e0d7d20174df742accc49c042cff17. Upgrading the affected component is recommended.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature), CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2026-4541?


## How do I fix CVE-2026-4541?

Upgrade to a fixed version.

## Is CVE-2026-4541 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4541 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4541 and fix it if it is affected.

What it is: CVE-2026-4541 is a low-severity vulnerability in janmojzis tinyssh, published on 22 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4541 exists.

Affected product: janmojzis tinyssh. 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-2026-4541/ (Markdown: https://insights.sbomify.com/CVE-2026-4541/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4541
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4541
- OSV: https://osv.dev/vulnerability/CVE-2026-4541

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4541/
Summaries are generated and may contain mistakes; the official description above is the record.