CVE-2021-0259: juniper networks junos os
Vulnerability summary
CVE-2021-0259 is a high (CVSS 7.4) vulnerability in juniper networks junos os. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.7% of scored vulnerabilities.
Timeline
- 22-04-2021PublishedVulnerability first disclosed.
- 16-09-2024Last modifiedVulnerability information updated.
Description
Due to a vulnerability in DDoS protection in Juniper Networks Junos OS and Junos OS Evolved on QFX5K Series switches in a VXLAN configuration, instability might be experienced in the underlay network as a consequence of exceeding the default ddos-protection aggregate threshold. If an attacker on a client device on the overlay network sends a high volume of specific, legitimate traffic in the overlay network, due to an improperly detected DDoS violation, the leaf might not process certain L2 traffic, sent by spines in the underlay network. Continued receipt and processing of the high volume traffic will sustain the Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS on QFX5K Series: 17.3 versions prior to 17.3R3-S11; 17.4 versions prior to 17.4R3-S5; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R2-S8, 18.2R3-S8; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R1-S8, 18.4R2-S6, 18.4R3-S6; 19.1 versions prior to 19.1R3-S4; 19.2 versions prior to 19.2R1-S6, 19.2R3-S2; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R2-S4, 19.4R3-S1; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2; 20.3 versions prior to 20.3R1-S2, 20.3R2. Juniper Networks Junos OS Evolved on QFX5220: All versions prior to 20.3R2-EVO.
CVSS metrics
3 scores · 2 sources · 2 versions- NVDNIST7.4HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS trend
Probability
0.38%
Chance of exploitation in the next 30 days
Percentile
31%
Versus all other CVEs
30-day change
0.00 pp
From 0.38% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Juniper2 products
- junos17.3 | 17.3:r1 | 17.3:r1-s1 | 17.3:r1-s4 | 17.3:r2 | 17.3:r2-s1 | 17.3:r2-s2 | 17.3:r2-s3 | 17.3:r2-s4 | 17.3:r2-s5 | 17.3:r3 | 17.3:r3-s1 | 17.3:r3-s10 | 17.3:r3-s2 | 17.3:r3-s3 | 17.3:r3-s4 | 17.3:r3-s5 | 17.3:r3-s6 | 17.3:r3-s7 | 17.3:r3-s8 | 17.3:r3-s9 | 17.4 | 17.4:r1 | 17.4:r1-s1 | 17.4:r1-s2 | 17.4:r1-s3 | 17.4:r1-s4 | 17.4:r1-s5 | 17.4:r1-s6 | 17.4:r1-s7 | 17.4:r2 | 17.4:r2-s1 | 17.4:r2-s10 | 17.4:r2-s11 | 17.4:r2-s2 | 17.4:r2-s3 | 17.4:r2-s4 | 17.4:r2-s5 | 17.4:r2-s6 | 17.4:r2-s7 | 17.4:r2-s8 | 17.4:r2-s9 | 17.4:r3 | 17.4:r3-s1 | 17.4:r3-s2 | 17.4:r3-s3 | 17.4:r3-s4 | 18.1 | 18.1:r1 | 18.1:r2 | 18.1:r2-s1 | 18.1:r2-s2 | 18.1:r2-s4 | 18.1:r3 | 18.1:r3-s1 | 18.1:r3-s10 | 18.1:r3-s11 | 18.1:r3-s12 | 18.1:r3-s2 | 18.1:r3-s3 | 18.1:r3-s4 | 18.1:r3-s5 | 18.1:r3-s6 | 18.1:r3-s7 | 18.1:r3-s8 | 18.1:r3-s9 | 18.2 | 18.2:r1 | 18.2:r1-s2 | 18.2:r1-s3 | 18.2:r1-s4 | 18.2:r1-s5 | 18.2:r2 | 18.2:r2-s1 | 18.2:r2-s2 | 18.2:r2-s3 | 18.2:r2-s4 | 18.2:r2-s5 | 18.2:r2-s6 | 18.2:r2-s7 | 18.2:r3 | 18.2:r3-s1 | 18.2:r3-s2 | 18.2:r3-s3 | 18.2:r3-s4 | 18.2:r3-s5 | 18.2:r3-s6 | 18.2:r3-s7 | 18.3 | 18.3:r1 | 18.3:r1-s1 | 18.3:r1-s2 | 18.3:r1-s3 | 18.3:r1-s4 | 18.3:r1-s5 | 18.3:r1-s6 | 18.3:r2 | 18.3:r2-s1 | 18.3:r2-s2 | 18.3:r2-s3 | 18.3:r2-s4 | 18.3:r3 | 18.3:r3-s1 | 18.3:r3-s2 | 18.3:r3-s3 | 18.3:r3-s4 | 18.4 | 18.4:r1 | 18.4:r1-s1 | 18.4:r1-s2 | 18.4:r1-s3 | 18.4:r1-s4 | 18.4:r1-s5 | 18.4:r1-s6 | 18.4:r1-s7 | 18.4:r2 | 18.4:r2-s1 | 18.4:r2-s2 | 18.4:r2-s3 | 18.4:r2-s4 | 18.4:r2-s5 | 18.4:r3 | 18.4:r3-s1 | 18.4:r3-s2 | 18.4:r3-s3 | 18.4:r3-s4 | 18.4:r3-s5 | 19.1 | 19.1:r1 | 19.1:r1-s1 | 19.1:r1-s2 | 19.1:r1-s3 | 19.1:r1-s4 | 19.1:r1-s5 | 19.1:r2 | 19.1:r2-s1 | 19.1:r3 | 19.1:r3-s1 | 19.1:r3-s2 | 19.1:r3-s3 | 19.2 | 19.2:r1 | 19.2:r1-s1 | 19.2:r1-s2 | 19.2:r1-s3 | 19.2:r1-s4 | 19.2:r1-s5 | 19.2:r2 | 19.2:r2-s1 | 19.2:r3 | 19.2:r3-s1 | 19.3 | 19.3:r1 | 19.3:r1-s1 | 19.3:r2 | 19.3:r2-s1 | 19.3:r2-s2 | 19.3:r2-s3 | 19.3:r2-s4 | 19.3:r2-s5 | 19.3:r3 | 19.3:r3-s1 | 19.4:r1 | 19.4:r1-s1 | 19.4:r1-s2 | 19.4:r1-s3 | 19.4:r2 | 19.4:r2-s1 | 19.4:r2-s2 | 19.4:r2-s3 | 19.4:r3 | 20.1:r1 | 20.1:r1-s1 | 20.1:r1-s2 | 20.1:r1-s3 | 20.1:r1-s4 | 20.2:r1 | 20.2:r1-s1 | 20.2:r1-s2 | 20.2:r1-s3 | 20.3:r1 | 20.3:r1-s1
- junos_os_evolved18.3:r1 | 19.1:r1 | 19.1:r2 | 19.2:r1 | 19.2:r2 | 19.3:r1 | 19.3:r2 | 20.1:r1 | 20.1:r2 | 20.2:r1 | 20.2:r2 | 20.3:r1
Juniper networks2 products
- junos os≥ 17.3, < 17.3R3-S11 | ≥ 17.4, < 17.4R3-S5 | ≥ 18.1, < 18.1R3-S13 | ≥ 18.2, < 18.2R2-S8, 18.2R3-S8 | ≥ 18.3, < 18.3R3-S5 | ≥ 18.4, < 18.4R1-S8, 18.4R2-S6, 18.4R3-S6 | ≥ 19.1, < 19.1R3-S4 | ≥ 19.2, < 19.2R1-S6, 19.2R3-S2 | ≥ 19.3, < 19.3R3-S2 | ≥ 19.4, < 19.4R2-S4, 19.4R3-S1 | ≥ 20.1, < 20.1R2 | ≥ 20.2, < 20.2R2 | ≥ 20.3, < 20.3R1-S2, 20.3R2
- junos os evolved≥ unspecified, < 20.3R2-EVO
2 vendors · 4 products