CyberSecBulletin
CVE-2023-36831NVD status: Modified

Junos OS: Improper Check or Handling of Exceptional Conditions

Published Updated By the CyberSecBulletin desk

CVE-2023-36831 is a high-severity improper check or handling of exceptional conditions vulnerability in Junos OS from Juniper Networks, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 22.2R3, 22.3R2-S1, 22.3R3, 22.4R1-S2, 22.4R2 as the first without the flaw, so updating Junos OS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.63% chance of exploitation within 30 days, higher than 51% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Junos OS to 22.2R3 or 22.3R2-S1, 22.3R3 or 22.4R1-S2, 22.4R2 or 22.3R2-S1, whichever matches your release line, or a later version.
  2. Read the advisory on supportportal.juniper.net for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Juniper NetworksJunos OS22.2 up to, but not including, 22.2R3; 22.3 up to, but not including, 22.3R2-S1, 22.3R3; 22.4 up to, but not including, 22.4R1-S2, 22.4R2; 22.3 up to, but not including, 22.3R2-S1; 22.3 up to, but not including, 22.3R3; 22.4 up to, but not including, 22.4R1-S2; 22.4 up to, but not including, 22.4R2; before 22.2R222.2R3, 22.3R2-S1, 22.3R3, 22.4R1-S2, 22.4R2, 22.3R2-S1, 22.3R3, 22.4R1-S2
Juniper NetworksJunos22.2; 22.3; 22.4Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (juniper.net).

Official description

An Improper Check or Handling of Exceptional Conditions vulnerability in the UTM (Unified Threat Management) Web-Filtering feature of Juniper Networks Junos OS on SRX Series causes a jbuf memory leak to occur when accessing certain websites, eventually leading to a Denial of Service (DoS) condition. Service restoration is only possible by rebooting the system. The jbuf memory leak only occurs in SSL Proxy and UTM Web-Filtering configurations. Other products, platforms, and configurations are not affected by this vulnerability. This issue affects Juniper Networks Junos OS on SRX Series: 22.2 versions prior to 22.2R3; 22.3 versions prior to 22.3R2-S1, 22.3R3; 22.4 versions prior to 22.4R1-S2, 22.4R2. This issue does not affect Juniper Networks Junos OS versions prior to 22.2R2.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Check or Handling of Exceptional Conditions

The product does not properly anticipate or handle exceptional conditions that rarely occur during normal operation of the product.

More Improper Check or Handling of Exceptional Conditions vulnerabilities (CWE-703)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Junos OS

All Junos OS vulnerabilities

Recent Improper Check or Handling of Exceptional Conditions vulnerabilities

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