CVE-2026-91085

MEDIUM
Published Sep 29, 2026 Modified Oct 1, 2026 CWE-862

Description

Apache Karaf's shell/SSH command security is enforced by per-scope ACL configuration files (etc/org.apache.karaf.command.acl.<scope>.cfg). SecuredSessionFactoryImpl.checkSecurity() resolves the roles required for an invocation and, when no ACL rule matches the command, fails open: ACLConfigurationParser.Specificity.NO_MATCH sets passCheck = true. The safety valve for this, karaf.secured.command.compulsory.roles, ships commented out in etc/system.properties, so an unmatched command is allowed for any authenticated user. The shipped org.apache.karaf.command.acl.config ACL (assemblies/features/standard/src/main/feature/feature.xml, mirrored into instance/.../etc/org.apache.karaf.command.acl.config.cfg) has no install entry. It restricts delete to admin, restricts edit/property-*/update on the jmx.acl.*, org.apache.karaf.command.acl.* and org.apache.karaf.service.acl.* PIDs to admin, and allows manager for everything else, but config:install was simply unmatched, and therefore allowed for any authenticated user, including one holding only the viewer role. config:install <url> <finalname> fetches url and writes it into ${karaf.etc} as finalname. It calls PathUtils.checkWithin() to block .. traversal outside karaf.etc, but that folder holds every security-relevant file Karaf ships: users.properties, keys.properties, host.key, and all org.apache.karaf.*.acl.* files, including the very ACL file that (mis)governs this command. With -o/--override, an existing file is overwritten with attacker-controlled bytes fetched from an arbitrary URL. Because felix.fileinstall.dir = ${karaf.etc} (etc/config.properties), Felix FileInstall also watches and reloads any .cfg file dropped there, closing the loop without requiring a restart. By contrast, bundle:install, feature:install and kar:install are all admin-only in their own ACLs, and config:delete is admin in this same ACL, config:install was the outlier. MitigationAdd install = admin in etc/org.apache.karaf.command.acl.config.cfg (create the file is absent), and/or set karaf.secured.command.compulsory.roles=admin in etc/system.properties (and restart) to make unmatched commands fail closed by default.

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CVSS v3.1 Score

6.3
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

EPSS — Exploit Prediction

0.0037
Probability of exploitation
0.31%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Frequently Asked Questions

What is CVE-2026-91085? +
Apache Karaf's shell/SSH command security is enforced by per-scope ACL configuration files (etc/org.apache.karaf.command.acl.<scope>.cfg). SecuredSessionFactoryImpl.checkSecurity() resolves the roles required for an invocation and, when no ACL rule matches the command, fails open: ACLConfigurationParser.Specificity.NO_MATCH sets passCheck = true. The safety valve for this, karaf.secured.command.compulsory.roles, ships commented out in etc/system.properties, so an unmatched command is allowed for any authenticated user. The shipped org.apache.karaf.command.acl.config ACL (assemblies/features/standard/src/main/feature/feature.xml, mirrored into instance/.../etc/org.apache.karaf.command.acl.config.cfg) has no install entry. It restricts delete to admin, restricts edit/property-*/update on the jmx.acl.*, org.apache.karaf.command.acl.* and org.apache.karaf.service.acl.* PIDs to admin, and allows manager for everything else, but config:install was simply unmatched, and therefore allowed for any authenticated user, including one holding only the viewer role. config:install <url> <finalname> fetches url and writes it into ${karaf.etc} as finalname. It calls PathUtils.checkWithin() to block .. traversal outside karaf.etc, but that folder holds every security-relevant file Karaf ships: users.properties, keys.properties, host.key, and all org.apache.karaf.*.acl.* files, including the very ACL file that (mis)governs this command. With -o/--override, an existing file is overwritten with attacker-controlled bytes fetched from an arbitrary URL. Because felix.fileinstall.dir = ${karaf.etc} (etc/config.properties), Felix FileInstall also watches and reloads any .cfg file dropped there, closing the loop without requiring a restart. By contrast, bundle:install, feature:install and kar:install are all admin-only in their own ACLs, and config:delete is admin in this same ACL, config:install was the outlier. MitigationAdd install = admin in etc/org.apache.karaf.command.acl.config.cfg (create the file is absent), and/or set karaf.secured.command.compulsory.roles=admin in etc/system.properties (and restart) to make unmatched commands fail closed by default. It has a CVSS v3.1 base score of 6.3 (MEDIUM).
How severe is CVE-2026-91085? +
CVE-2026-91085 has a CVSS v3.1 score of 6.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0037, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-91085? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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