CVE detail

CVE-2021-0277 — CVE-2021-0277

Published 2021-07-15 · Modified 2026-06-17 · Vendor juniper · Product junos · Source nvd
HIGH
severity
CVSS-derived band
8.8
CVSS v3
0–10 scale
0.0065
EPSS probability
exploitation probability, 30d
48.0%
EPSS percentile
percentile vs all CVEs
NOT LISTED
CISA KEV
known exploited catalog

Description

An Out-of-bounds Read vulnerability in the processing of specially crafted LLDP frames by the Layer 2 Control Protocol Daemon (l2cpd) of Juniper Networks Junos OS and Junos OS Evolved may allow an attacker to cause a Denial of Service (DoS), or may lead to remote code execution (RCE). Continued receipt and processing of these frames, sent from the local broadcast domain, will repeatedly crash the l2cpd process and sustain the Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS: 12.3 versions prior to 12.3R12-S18; 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S12; 17.4 versions prior to 17.4R2-S13, 17.4R3-S5; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R3-S8; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R2-S8,

Remediation

vendor remediation guidance

The following software releases have been updated to resolve this specific issue: Junos OS 12.3R12-S18, 15.1R7-S9, 17.3R3-S12, 17.4R2-S13, 17.4R3-S5, 18.1R3-S13, 18.2R3-S8, 18.3R3-S5, 18.4R2-S8, 18.4R3-S8, 19.1R3-S5, 19.3R2-S6, 19.3R3-S2, 19.4R1-S4, 19.4R2-S4, 19.4R3-S3, 20.1R2-S2, 20.1R3, 20.2R3-S1, 20.3R2-S1, 20.3R3, 20.4R2, 20.4R3, 21.1R1, 21.1R2, 21.2R1, and all subsequent releases. Junos OS Evolved 20.4R2-EVO, 21.1R1-EVO, and all subsequent releases.

workarounds

1. Configure the device to not load the L2CPD daemon using the following CLI config stanza. set system processes l2cpd-service disable Additional protocols L2CPD daemon supports include RSTP, MSTP, VSTP, ERP, xSTP and ERP protocols. After issuing set system processes l2cpd-service disable, RSTP, MSTP, VSTP, ERP, xSTP and ERP protocols will cease to operate. Please note, this is not an exhaustive list, disabling L2CPD may affect other protocols and services that rely upon L2CPD daemon to be present. For example, L2ALD, MRVP, EVPN traffic, etc. may also cease to operate. To avoid downtime, customers considering applying this workaround should carefully test all workaround changes to their environment in a non-production environment first that mirrors or as closely as possible matches the production environment before applying to the production environment. 2. Configure target interfaces on the device to disable LLDP packet processing: set protocols lldp interface <interface name> disable 3. On Switching platforms such as EX/QFX Series devices implement packet filters to discard LLDP packets with an EtherType of 0x88cc. For example: set firewall family ethernet-switching filter LLDP_EXAMPLE term 1 from ether-type 0x88cc set firewall family ethernet-switching filter LLDP_EXAMPLE term 1 then discard Workaround #3 does not work on MX Series devices. MX Series devices should disable LLDP processing, filter off-system, or upgrade to a fixed release. 4. Lastly, as a method to reduce t

ProductVulnerable rangeFixed versionAdvisory
Juniper Networks Junos OS>=12.3<12.3R12-S1812.3R12-S18advisory ↗
Juniper Networks Junos OS>=15.1<15.1R7-S915.1R7-S9advisory ↗
Juniper Networks Junos OS>=17.3<17.3R3-S1217.3R3-S12advisory ↗
Juniper Networks Junos OS>=17.4<17.4R2-S13, 17.4R3-S517.4R2-S13, 17.4R3-S5advisory ↗
Juniper Networks Junos OS>=18.1<18.1R3-S1318.1R3-S13advisory ↗
Juniper Networks Junos OS>=18.2<18.2R3-S818.2R3-S8advisory ↗
Juniper Networks Junos OS>=18.3<18.3R3-S518.3R3-S5advisory ↗
Juniper Networks Junos OS>=18.4<18.4R2-S8, 18.4R3-S818.4R2-S8, 18.4R3-S8advisory ↗
Juniper Networks Junos OS>=19.1<19.1R3-S519.1R3-S5advisory ↗
Juniper Networks Junos OS>=19.2<19.2R3-S319.2R3-S3advisory ↗
Juniper Networks Junos OS>=19.3<19.3R2-S6, 19.3R3-S219.3R2-S6, 19.3R3-S2advisory ↗
Juniper Networks Junos OS>=19.4<19.4R1-S4, 19.4R2-S4, 19.4R3-S319.4R1-S4, 19.4R2-S4, 19.4R3-S3advisory ↗
Juniper Networks Junos OS>=20.1<20.1R2-S2, 20.1R320.1R2-S2, 20.1R3advisory ↗
Juniper Networks Junos OS>=20.2<20.2R3-S120.2R3-S1advisory ↗
Juniper Networks Junos OS>=20.3<20.3R2-S1, 20.3R320.3R2-S1, 20.3R3advisory ↗
Juniper Networks Junos OS>=20.4<20.4R220.4R2advisory ↗
Juniper Networks Junos OS Evolved>=unspecified<20.4R2-EVO20.4R2-EVOadvisory ↗

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.