Junos OS: Improper Validation of Syntactic Correctness of Input
CVE-2024-21616 is a high-severity improper validation of syntactic correctness of input 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 21.2R3-S6, 21.3R3-S5, 21.4R3-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 0.53% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Junos OS to 21.2R3-S6 or 21.3R3-S5 or 21.4R3-S5 or 22.1R3-S4, whichever matches your release line, 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 21.2R3-S6; 21.3 up to, but not including, 21.3R3-S5; 21.4 up to, but not including, 21.4R3-S5; 22.1 up to, but not including, 22.1R3-S4; 22.2 up to, but not including, 22.2R3-S3; 22.3 up to, but not including, 22.3R3-S1; 22.4 up to, but not including, 22.4R2-S2, 22.4R3; 23.2 up to, but not including, 23.2R1-S1, 23.2R2 | 21.2R3-S6, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, 22.2R3-S3, 22.3R3-S1 |
| Juniper Networks | Junos | 21.2; 21.3; 21.4; 22.1; 22.2; 22.3; 22.4; 23.2 | Not 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 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 Improper Validation of Syntactic Correctness of Input vulnerability in Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows an unauthenticated, network-based attacker to cause Denial of Service (DoS). On all Junos OS MX Series and SRX Series platforms, when SIP ALG is enabled, and a specific SIP packet is received and processed, NAT IP allocation fails for genuine traffic, which causes Denial of Service (DoS). Continuous receipt of this specific SIP ALG packet will cause a sustained DoS condition. NAT IP usage can be monitored by running the following command. user@srx> show security nat resource-usage source-pool <source_pool_name> Pool name: source_pool_name .. Address Factor-index Port-range Used Avail Total Usage X.X.X.X 0 Single Ports 50258 52342 62464 96% <<<<< - Alg Ports 0 2048 2048 0% This issue affects: Juniper Networks Junos OS on MX Series and SRX Series * All versions earlier than 21.2R3-S6; * 21.3 versions earlier than 21.3R3-S5; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3-S4; * 22.2 versions earlier than 22.2R3-S3; * 22.3 versions earlier than 22.3R3-S1; * 22.4 versions earlier than 22.4R2-S2, 22.4R3; * 23.2 versions earlier than 23.2R1-S1, 23.2R2.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Validation of Syntactic Correctness of Input
The product receives input that is expected to be well-formed - i.e., to comply with a certain syntax - but it does not validate or incorrectly validates that the input complies with the syntax.
More Improper Validation of Syntactic Correctness of Input vulnerabilities (CWE-1286)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
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 Improper Validation of Syntactic Correctness of Input vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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