CVE-2026-91012

Description

org.apache.karaf.config.core.impl.ConfigRepositoryImpl#update(pid, properties), which backs the "config" MBean and the config:* shell commands, derives the file it writes a configuration to from caller-supplied input without checking that the result stays inside ${karaf.etc}: * if the submitted property map contains a felix.fileinstall.filename entry, that value is turned directly into a File (getCfgFileFromProperty), so it can point to any absolute path the Karaf process can write to; * otherwise the configuration PID is concatenated verbatim into the target file name (generateConfigFilename(): new File(karaf.etc, pid + ".cfg")), so a PID containing ".." segments resolves outside ${karaf.etc}. createFactoryConfiguration() has the same issue via the factory PID/alias. Both code paths are reachable by any caller holding the "manager" role under Karaf's shipped command/JMX ACL (org.apache.karaf.command.acl.conf.cfg: "update = manager"). Such a user can therefore write attacker-controlled content to any file the Karaf process can write, including files the same ACL otherwise reserves to "admin" (etc/users.properties, etc/*.acl.*.cfg, etc/org.apache.karaf.management.cfg, and similar), allowing a manager-role user to grant themselves the admin role or otherwise take over the container. ConfigMBeanImpl.install() and the config:install shell command already guarded the equivalent risk on their own code path with a finalname.contains("..") string check, but that check does not stop absolute paths or symlink-based escapes, and it was never applied to ConfigRepositoryImpl.update() / createFactoryConfiguration() at all.

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EPSS — Exploit Prediction

0.0017

Probability of exploitation

0.06%

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.

References

Other References

https://lists.apache.org/thread/op8trtz1qxkdwj2rjozhd9yt2yd6nhw4 http://www.openwall.com/lists/oss-security/2026/09/28/8

Frequently Asked Questions

What is CVE-2026-91012? +

org.apache.karaf.config.core.impl.ConfigRepositoryImpl#update(pid, properties), which backs the "config" MBean and the config:* shell commands, derives the file it writes a configuration to from caller-supplied input without checking that the result stays inside ${karaf.etc}: * if the submitted property map contains a felix.fileinstall.filename entry, that value is turned directly into a File (getCfgFileFromProperty), so it can point to any absolute path the Karaf process can write to; * otherwise the configuration PID is concatenated verbatim into the target file name (generateConfigFilename(): new File(karaf.etc, pid + ".cfg")), so a PID containing ".." segments resolves outside ${karaf.etc}. createFactoryConfiguration() has the same issue via the factory PID/alias. Both code paths are reachable by any caller holding the "manager" role under Karaf's shipped command/JMX ACL (org.apache.karaf.command.acl.conf.cfg: "update = manager"). Such a user can therefore write attacker-controlled content to any file the Karaf process can write, including files the same ACL otherwise reserves to "admin" (etc/users.properties, etc/*.acl.*.cfg, etc/org.apache.karaf.management.cfg, and similar), allowing a manager-role user to grant themselves the admin role or otherwise take over the container. ConfigMBeanImpl.install() and the config:install shell command already guarded the equivalent risk on their own code path with a finalname.contains("..") string check, but that check does not stop absolute paths or symlink-based escapes, and it was never applied to ConfigRepositoryImpl.update() / createFactoryConfiguration() at all.

How do I check if I'm vulnerable to CVE-2026-91012? +

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.