CVE-2024-39517 — An Improper Check for Unusual or Exceptional Conditions vulnerability in the Lay

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Layer 2 Address Learning Daemon (l2ald) on Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker to cause Denial of Service (DoS).

01What is this vulnerability?

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Layer 2 Address Learning Daemon (l2ald) on Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker to cause Denial of Service (DoS).

02Affected products

Vendor	Product	Versions
Juniper Networks	Junos OS	0, 21.4, 22.1, 22.2, 22.3, 22.4, 23.2, 23.4
Juniper Networks	Junos OS Evolved	0, 21.4-EVO, 22.1-EVO, 22.2-EVO, 22.3-EVO, 22.4-EVO, 23.2-EVO, 23.4-EVO

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

Open in Sigma generator →

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2024-07-10T23:06:40.329Z
• Last modified: 2024-08-02T04:26:15.885Z

09References

• supportportal.juniper.net — https://supportportal.juniper.net/JSA79175