There is a flaw in polkit which can allow an unprivileged user to cause polkit to crash, due to process file descriptor exhaustion.

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• canonical ubuntu linux20.04
• canonical ubuntu linux21.10
• debian debian linux11.0
• fedoraproject fedora34
• fedoraproject fedora35
• oracle zfs storage appliance kit8.8
• polkit project polkit0.117
• redhat enterprise linux8.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

• n/a polkitd

  • 0.117affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2021-4034A local privilege escalation vulnerability was found on polkit's pkexec utility.KEV
  89Now
• CVE-2021-3560It was found that polkit could be tricked into bypassing the credential checks for D-Bus requests, elevating the privileges of the requestorKEV
  68This week
• CVE-2018-19788A flaw was found in PolicyKit (aka polkit) 0.115 that allows a user with a uid greater than INT_MAX to successfully execute any systemctl co
  38Monitor
• CVE-2019-6133In PolicyKit (aka polkit) 0.115, the "start time" protection mechanism can be bypassed because fork() is not atomic, and therefore authoriza
  26Monitor
• CVE-2015-3256PolicyKit (aka polkit) before 0.113 allows local users to cause a denial of service (memory corruption and polkitd daemon crash) and possibl
  18Monitor
• CVE-2015-3255The polkit_backend_action_pool_init function in polkitbackend/polkitbackendactionpool.c in PolicyKit (aka polkit) before 0.113 might allow l
  18Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1function expand(node) {2  return node.children.map(expand);3}

1const MAX_DEPTH = 32;2function expand(node, depth = 0) {3  if (depth > MAX_DEPTH) throw new Error("too deep");4  return node.children.map((c) => expand(c, depth + 1));5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.