CVE-2021-0264
MEDIUMDescription
A vulnerability in the processing of traffic matching a firewall filter containing a syslog action in Juniper Networks Junos OS on MX Series with MPC10/MPC11 cards installed, PTX10003 and PTX10008 Series devices, will cause the line card to crash and restart, creating a Denial of Service (DoS). Continued receipt and processing of packets matching the firewall filter can create a sustained Denial of Service (DoS) condition. When traffic hits the firewall filter, configured on lo0 or any physical interface on the line card, containing a term with a syslog action (e.g. 'term <name> then syslog'), the affected line card will crash and restart, impacting traffic processing through the ports of the line card. This issue only affects MX Series routers with MPC10 or MPC11 line cards, and PTX10003 or PTX10008 Series packet transport routers. No other platforms or models of line cards are affected by this issue. Note: This issue has also been identified and described in technical service bulletin TSB17931 (login required). This issue affects: Juniper Networks Junos OS on MX Series: 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-S2, 20.2R3; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R2. Juniper Networks Junos OS Evolved on PTX10003, PTX10008: All versions prior to 20.4R2-EVO. This issue does not affect Juniper Networks Junos OS versions prior to 19.3R1.
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.
TridentStack Control tracks known vulnerabilities across your Windows, macOS, and Linux fleet and shows the fix as soon as one is published. See how it works
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 59% 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-2021-0264?
No published fix for CVE-2021-0264 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2021-0264 being actively exploited?
Not that we know of. CVE-2021-0264 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.98% is the estimated probability that it will be exploited in the next 30 days. That is higher than 59% of all scored CVEs.
How severe is CVE-2021-0264?
CVE-2021-0264 has a CVSS v3 base score of 5.9, rated medium. 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-2021-0264
Markdown
[](https://tridentstack.com/cve/CVE-2021-0264)HTML
<a href="https://tridentstack.com/cve/CVE-2021-0264"><img src="https://tridentstack.com/cve/badge/CVE-2021-0264.svg" alt="CVE-2021-0264"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
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.