Junos OS: Loop with Unreachable Exit Condition
CVE-2023-44181 is a high-severity loop with unreachable exit condition 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 20.2R3-S6, 20.3R3-S5, 20.4R3-S5 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 0.64% chance of exploitation within 30 days, higher than 51% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Junos OS to 20.2R3-S6 or 20.3R3-S5 or 20.4R3-S5 or 21.1R3-S4, whichever matches your release line, or a later version.
- Update Junos to 20.2 or a later version.
- Read the advisory on supportportal.juniper.net for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Juniper Networks | Junos OS | before 20.2R3-S6; 20.3 up to, but not including, 20.3R3-S5; 20.4 up to, but not including, 20.4R3-S5; 21.1 up to, but not including, 21.1R3-S4; 21.2 up to, but not including, 21.2R3-S3; 21.3 up to, but not including, 21.3R3-S2; 21.4 up to, but not including, 21.4R3; 22.1 up to, but not including, 22.1R3; and 1 more ranges | 20.2R3-S6, 20.3R3-S5, 20.4R3-S5, 21.1R3-S4, 21.2R3-S3, 21.3R3-S2 |
| Juniper Networks | Junos | before 20.2; 20.2; 20.3; 20.4; 21.1; 21.2; 21.3; 21.4; and 2 more ranges | 20.2 |
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 NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (juniper.net) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
An Improperly Implemented Security Check for Standard vulnerability in storm control of Juniper Networks Junos OS QFX5k devices allows packets to be punted to ARP queue causing a l2 loop resulting in a DDOS violations and DDOS syslog. This issue is triggered when Storm control is enabled and ICMPv6 packets are present on device. This issue affects Juniper Networks: Junos OS * All versions prior to 20.2R3-S6 on QFX5k; * 20.3 versions prior to 20.3R3-S5 on QFX5k; * 20.4 versions prior to 20.4R3-S5 on QFX5k; * 21.1 versions prior to 21.1R3-S4 on QFX5k; * 21.2 versions prior to 21.2R3-S3 on QFX5k; * 21.3 versions prior to 21.3R3-S2 on QFX5k; * 21.4 versions prior to 21.4R3 on QFX5k; * 22.1 versions prior to 22.1R3 on QFX5k; * 22.2 versions prior to 22.2R2 on QFX5k.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Loop with Unreachable Exit Condition
The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
More Loop with Unreachable Exit Condition vulnerabilities (CWE-835)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other references
Other vulnerabilities in Junos OS
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 7.5 High severity
Recent Loop with Unreachable Exit Condition vulnerabilities
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- 7.5 High severity
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- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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