CVE-2020-1660
Junos OS: MX Series: Receipt of specific packets can cause services card to restart when DNS filtering is configured.
- Published
- Updated
- Reserved
- Assigned by
- juniper
Description
When DNS filtering is enabled on Juniper Networks Junos MX Series with one of the following cards MS-PIC, MS-MIC or MS-MPC, an incoming stream of packets processed by the Multiservices PIC Management Daemon (mspmand) process, responsible for managing "URL Filtering service", may crash, causing the Services PIC to restart. While the Services PIC is restarting, all PIC services including DNS filtering service (DNS sink holing) will be bypassed until the Services PIC completes its boot process. This vulnerability might allow an attacker to cause an extended Denial of Service (DoS) attack against the device and to cause clients to be vulnerable to DNS based attacks by malicious DNS servers when they send DNS requests through the device. As a result, devices which were once protected by the DNS Filtering service are no longer protected and at risk of exploitation. This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S8; 18.3 versions prior to 18.3R3-S1; 18.4 versions prior to 18.4R3; 19.1 versions prior to 19.1R3; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R3. This issue does not affect Juniper Networks Junos OS 17.4, 18.1, and 18.2.
Timeline
ID reserved
By juniper
- 12 months later
· 12 months later
Published
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| juniperCNA (assigner) | 3.1 | High8.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L |
| NVDNVD · Modified | 3.1 | Critical9.9 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:H |
- EPSS (exploitation in 30 days)
- 0.79% · top 43% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.3.
Weakness
Affected products
- affected 17.3 – < 17.3R3-S8
- affected 18.3 – < 18.3R3-S1
- affected 18.4 – < 18.4R3
- affected 19.1 – < 19.1R3
- affected 19.2 – < 19.2R2
- affected 19.3 – < 19.3R3
- unaffected 17.4
- unaffected 18.1
- unaffected 18.2
What to do
Solution: The following software releases have been updated to resolve this specific issue: Junos OS 17.3R3-S8, 18.3R3-S1, 18.4R3, 19.1R3, 19.2R2, 19.3R3, 19.4R1 and all subsequent releases.
Workaround: There are no viable workarounds for this issue.
Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
References (1)
- https://kb.juniper.net/JSA11054 (opens in a new tab)x_refsource_CONFIRMx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2020-1660)Record last updated .