CVE detail

CVE-2021-0254 — CVE-2021-0254

Published 2021-04-22 · Modified 2026-06-17 · Vendor juniper · Product junos · Source nvd
CRITICAL
severity
CVSS-derived band
9.8
CVSS v3
0–10 scale
0.0257
EPSS probability
exploitation probability, 30d
84.0%
EPSS percentile
percentile vs all CVEs
NOT LISTED
CISA KEV
known exploited catalog

Description

A buffer size validation vulnerability in the overlayd service of Juniper Networks Junos OS may allow an unauthenticated remote attacker to send specially crafted packets to the device, triggering a partial Denial of Service (DoS) condition, or leading to remote code execution (RCE). Continued receipt and processing of these packets will sustain the partial DoS. The overlayd daemon handles Overlay OAM packets, such as ping and traceroute, sent to the overlay. The service runs as root by default and listens for UDP connections on port 4789. This issue results from improper buffer size validation, which can lead to a buffer overflow. Unauthenticated attackers can send specially crafted packets to trigger this vulnerability, resulting in possible remote code execution. overlayd runs by defaul

Remediation

vendor remediation guidance

The following software releases have been updated to resolve this specific issue: Junos OS 15.1X49-D240, 15.1R7-S9, 17.3R3-S11, 17.4R2-S13, 17.4R3-S4, 18.1R3-S12, 18.2R2-S8, 18.2R3-S7, 18.3R3-S4, 18.4R1-S8, 18.4R2-S7, 18.4R3-S7, 19.1R2-S2, 19.1R3-S4, 19.2R1-S6, 19.2R3-S2, 19.3R3-S1, 19.4R2-S4, 19.4R3-S1, 20.1R2-S1, 20.1R3, 20.2R2, 20.2R2-S1, 20.2R3, 20.3R1-S1, 20.4R1, and all subsequent releases. This fix has also been proactively committed into other releases that might not be vulnerable to this issue.

workarounds

Two methods exist to mitigate this issue: 1. Limit the exploitable attack surface of critical infrastructure networking equipment by using access lists or firewall filters to limit access to the device via UDP only from trusted, administrative networks or hosts. 2. Disable Overlay OAM packet via the configuration command: 'set system processes overlay-ping-traceroute disable'

ProductVulnerable rangeFixed versionAdvisory
Juniper Networks Junos OS>=15.1<15.1R7-S915.1R7-S9advisory ↗
Juniper Networks Junos OS>=17.3<17.3R3-S1117.3R3-S11advisory ↗
Juniper Networks Junos OS>=17.4<17.4R2-S13, 17.4R3-S417.4R2-S13, 17.4R3-S4advisory ↗
Juniper Networks Junos OS>=18.1<18.1R3-S1218.1R3-S12advisory ↗
Juniper Networks Junos OS>=18.2<18.2R2-S8, 18.2R3-S718.2R2-S8, 18.2R3-S7advisory ↗
Juniper Networks Junos OS>=18.3<18.3R3-S418.3R3-S4advisory ↗
Juniper Networks Junos OS>=18.4<18.4R1-S8, 18.4R2-S7, 18.4R3-S718.4R1-S8, 18.4R2-S7, 18.4R3-S7advisory ↗
Juniper Networks Junos OS>=19.1<19.1R2-S2, 19.1R3-S419.1R2-S2, 19.1R3-S4advisory ↗
Juniper Networks Junos OS>=19.2<19.2R1-S6, 19.2R3-S219.2R1-S6, 19.2R3-S2advisory ↗
Juniper Networks Junos OS>=19.3<19.3R3-S119.3R3-S1advisory ↗
Juniper Networks Junos OS>=19.4<19.4R2-S4, 19.4R3-S119.4R2-S4, 19.4R3-S1advisory ↗
Juniper Networks Junos OS>=20.1<20.1R2-S1, 20.1R320.1R2-S1, 20.1R3advisory ↗
Juniper Networks Junos OS>=20.2<20.2R2, 20.2R2-S1, 20.2R320.2R2, 20.2R2-S1, 20.2R3advisory ↗
Juniper Networks Junos OS>=20.3<20.3R1-S120.3R1-S1advisory ↗

References

cvedb.io · NVD · CISA KEV · FIRST EPSS · vendor advisories (CVE Program List v5). Informational only, no warranty — verify every remediation against the vendor advisory before acting on it. This product uses data from the NVD API but is not endorsed or certified by the NVD, CISA, FIRST.org or any vendor named. CVE® is a registered trademark of The MITRE Corporation.