CVE-2021-31383Junos OS and Junos OS Evolved: In Point to MultiPoint (P2MP) scenarios receipt of various crafted packets causes RPD to core.
- 7.5HighCVSS base score
- 1.0%Exploitation in 30 daysEPSS · top 36% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In Point to MultiPoint (P2MP) scenarios within established sessions between network or adjacent neighbors the improper use of a source to destination copy write operation combined with a Stack-based Buffer Overflow on certain specific packets processed by the routing protocol daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved sent by a remote unauthenticated network attacker causes the RPD to crash causing a Denial of Service (DoS). Continued receipt and processing of these packets will create a sustained Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS 19.2 versions prior to 19.2R3-S2; 19.3 versions prior to 19.3R2-S6, 19.3R3-S2; 19.4 versions prior to 19.4R1-S4, 19.4R2-S4, 19.4R3-S3; 20.1 versions prior to 20.1R2-S2, 20.1R3; 20.2 versions prior to 20.2R2-S3, 20.2R3; 20.3 versions prior to 20.3R2. This issue does not affect Juniper Networks Junos OS versions prior to 19.2R1. Juniper Networks Junos OS Evolved 20.1 versions prior to 20.1R3-EVO; 20.2 versions prior to 20.2R3-EVO; 20.3 versions prior to 20.3R2-EVO.
Timeline
ID reserved
By juniper
- 6 months later
· 6 months later
Published
- 3 years later
· 3 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 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 1.0% · top 36% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
- unaffected unspecified – < 19.2R1
- affected 19.2 – < 19.2R3-S2
- affected 19.3 – < 19.3R2-S6, 19.3R3-S2
- affected 19.4 – < 19.4R1-S4, 19.4R2-S4, 19.4R3-S3
- affected 20.1 – < 20.1R2-S2, 20.1R3
- affected 20.2 – < 20.2R2-S3, 20.2R3
- affected 20.3 – < 20.3R2
Juniper Networks · Junos OS Evolved
- affected 20.1 – < 20.1R3-EVO
- affected 20.2 – < 20.2R3-EVO
- affected 20.3 – < 20.3R2-EVO
What to do
Solution: The following software releases have been updated to resolve this specific issue: Junos OS: 19.2R3-S2, 19.3R2-S6, 19.3R3-S2, 19.4R1-S4, 19.4R2-S4, 19.4R3-S3, 20.1R2-S2, 20.1R3, 20.2R2-S3, 20.2R3, 20.3R2, 20.4R1, and all subsequent releases. Junos OS Evolved: 20.1R3-EVO, 20.2R3-EVO, 20.3R2-EVO, 20.4R1-EVO, and all subsequent releases.
Workaround: For Junos OS you can remove the traffic-statistics from the configuration to work around this issue. [protoccols ldp traffic-statistics {sensor-based-stats;}] For Junos OS Evolved there are no viable workarounds for this issue.
Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
References
References1
- https://kb.juniper.net/JSA11251 (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)
- EUVD EUVD-2021-18293 (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://cveledger.app/cve/CVE-2021-31383)Record last updated .