Vulnerability in Juniper Junos
CVE-2025-21591
A Buffer Access with Incorrect Length Value vulnerability in the jdhcpd daemon of Juniper Networks Junos OS, when DHCP snooping is enabled, allows an unauthenticated, adjacent, attacker to send a DHCP packet with a malformed DHCP option to cause jdhcp to crash creating a Denial of Service (DoS) condition. Continuous receipt of these DHCP packets using the malformed DHCP Option will create a sustained Denial of Service (DoS) condition. This issue affects Junos OS: * from 23.1 before 23.2R2-S3, * from 23.4 before 23.4R2-S3, * from 24.2 before 24.2R2. This issue isn't applicable to any versions of Junos OS before 23.1R1. This issue doesn't affect vSRX Series which doesn't support DHCP Snooping. This issue doesn't affect Junos OS Evolved. There are no indicators of compromise for this issue.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.003 (24.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- Juniper Junos — versions 23.1, 23.2, 23.4
- Juniper Networks Junos OS — versions 23.1, 23.4, 24.2
Weakness classification (CWE)
References
- supportportal.juniper.net/JSA96448 (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2025-21591?
- CVE-2025-21591 is a high-severity vulnerability in Juniper Junos, classified under Buffer Access with Incorrect Length Value. CVSS score: 7.4/10. Published 2025-04-09.
- How severe is CVE-2025-21591?
- High severity. CVSS v3 base score is 7.4 out of 10.