CVE-2026-86231

mwiede jsch KnownHosts.java getRevokedKeys improper check for certificate revocation

State: Published
Severity: 6.3 Medium
Published: Sep 6, 2026
Updated: Sep 11, 2026
Reserved: Sep 6, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	6.3 Medium	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	VulDB
3.1	3.7 Low	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N/E:P/RL:O/RC:C	VulDB
3.0	3.7 Low	CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N/E:P/RL:O/RC:C	VulDB
2.0	2.6 Low	AV:N/AC:H/Au:N/C:N/I:P/A:N/E:POC/RL:OF/RC:C	VulDB

Weaknesses

CWE-299 Improper Check for Certificate Revocation
CWE-298 Improper Validation of Certificate Expiration

Affected Products

Product	Versions
jschmwiede	2.28.0Affected 2.28.1Affected 2.28.2Affected 2.28.3Affected 2.28.4Affected 2.28.5Affected 2.28.6Not affected

References

VDB-399388 | mwiede jsch KnownHosts.java getRevokedKeys improper check for certificate revocationvdb-entrytechnical-description
VDB-399388 | CTI Indicators (IOB, IOC, TTP, IOA)signaturepermissions-required
CVE-2026-86231 | CVE Analysis and Reportthird-party-advisory
Submit #898485 | mwiede jsch 2.28.4 Cert Revocation Type String Bypassthird-party-advisory
https://github.com/mwiede/jsch/issues/1091exploitissue-tracking
https://github.com/mwiede/jsch/pull/1098issue-trackingpatch
https://github.com/mwiede/jsch/commit/194a2f76a5c0f1c3f778565be3fd66bcafc42d23patch
https://github.com/mwiede/jsch/releases/tag/jsch-2.28.6patch
https://github.com/mwiede/jsch/product

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