CVE-2021-0240
HIGHDescription
On Juniper Networks Junos OS platforms configured as DHCPv6 local server or DHCPv6 Relay Agent, the Juniper Networks Dynamic Host Configuration Protocol Daemon (JDHCPD) process might crash if a malformed DHCPv6 packet is received, resulting in a restart of the daemon. The daemon automatically restarts without intervention, but continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue only affects DHCPv6. DHCPv4 is not affected by this issue. This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S12; 17.4 versions prior to 17.4R3-S5; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R3-S8; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R1-S8, 18.4R3-S7; 19.1 versions prior to 19.1R3-S5; 19.2 versions prior to 19.2R3-S2; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R3-S2; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R2-S3, 20.2R3; 20.3 versions prior to 20.3R2; 20.4 versions prior to 20.4R2.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 33% of all known CVEs.
References
Related Vulnerabilities
Other CWE-703 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-21894 | Critical | 9.8 | 19% | - | - |
| CVE-2025-59538 | High | 7.5 | 8.3% | - | Fix |
| CVE-2019-5031 | High | 8.8 | 6.0% | - | - |
| CVE-2023-49786 | High | 7.5 | 5.3% | - | Fix |
| CVE-2024-10781 | High | 8.1 | 3.8% | - | Fix |
| CVE-2024-22052 | High | 7.5 | 3.8% | - | - |
Common questions
How do I fix CVE-2021-0240?
No published fix for CVE-2021-0240 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2021-0240 being actively exploited?
Not that we know of. CVE-2021-0240 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.40% is the estimated probability that it will be exploited in the next 30 days. That is higher than 33% of all scored CVEs.
How severe is CVE-2021-0240?
CVE-2021-0240 has a CVSS v3 base score of 7.4, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
Embed a live status badge for CVE-2021-0240
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.