# CVE-2026-86231: mwiede jsch KnownHosts.java getRevokedKeys improper check for certificate revocation

> Attackers can bypass certificate revocation checks in the jsch library by manipulating known_hosts, potentially allowing connections to revoked keys.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Sep 2026
- **Updated:** 11 Sep 2026
- **Also known as:** CLEANSTART-2026-JS37598, CLEANSTART-2026-YJ32154, DEBIAN-CVE-2026-86231, GHSA-x2rp-h5qg-fmqg, UBUNTU-CVE-2026-86231, openSUSE-SU-2026:11814-1

## What is CVE-2026-86231?

CVE-2026-86231 is a medium-severity vulnerability in mwiede jsch, published on 6 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A security flaw has been discovered in mwiede jsch up to 2.28.5. Affected is the function getRevokedKeys of the file src/main/java/com/jcraft/jsch/KnownHosts.java. Performing a manipulation of the argument known_hosts results in improper check for certificate revocation. The attack is possible to be carried out remotely. The attack is considered to have high complexity. The exploitability is told to be difficult. The exploit has been released to the public and may be used for attacks. Upgrading to version 2.28.6 is able to address this issue. The patch is named 194a2f76a5c0f1c3f778565be3fd66bcafc42d23. You should upgrade the affected component.

Weakness: CWE-299 (Improper Check for Certificate Revocation), CWE-298 (Improper Validation of Certificate Expiration)

## Which versions are affected by CVE-2026-86231?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `jsch` | openSUSE:Tumbleweed | All versions | 2.28.7-1.1 |

## How do I fix CVE-2026-86231?

Upgrade to a fixed version.

## Is CVE-2026-86231 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86231 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-86231 and fix it if it is affected.

What it is: CVE-2026-86231 is a medium-severity vulnerability in mwiede jsch, published on 6 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86231 exists.

Affected product: mwiede jsch. 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-2026-86231/ (Markdown: https://insights.sbomify.com/CVE-2026-86231/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-86231
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-86231
- OSV: https://osv.dev/vulnerability/CVE-2026-86231

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-86231/
Summaries are generated and may contain mistakes; the official description above is the record.