CVE-2021-31383Network attack vector

RPD crash via improper packet copy

Published Oct 19, 2021 · Updated Sep 16, 2024

Stack-based buffer overflow in RPD in affected Juniper Networks Junos OS and Junos OS Evolved releases allows remote attackers to crash RPD. RPD performs an improper source-to-destination copy while processing crafted packets in an established P2MP session, overflowing a stack buffer. The affected LDP P2MP configuration and an established network- or adjacency-level neighbor session are required, and continued packet delivery sustains the service interruption.

CVSS severity7.5
High
EPSS probability1.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stack-based buffer overflow in RPD in affected Juniper Networks Junos OS and Junos OS Evolved releases allows remote attackers to crash RPD. RPD performs an improper source-to-destination copy while processing crafted packets in an established P2MP session, overflowing a stack buffer. The affected LDP P2MP configuration and an established network- or adjacency-level neighbor session are required, and continued packet delivery sustains the service interruption.

The record

CVE
CVE-2021-31383
Published
Oct 19, 2021
Updated
Sep 16, 2024
Vendor
Juniper Networks
Product
Junos OS Evolved
Classifications
CWE-121, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=20.1 <20.1R3-EVO
  2. Affected versionversion=20.2 <20.2R3-EVO
  3. Affected versionversion=20.3 <20.3R2-EVO

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OS Evolvedversion=20.1 <20.1R3-EVO; version=20.2 <20.2R3-EVO; version=20.3 <20.3R2-EVO
Juniper Networks · Junos OSversion=19.2 <19.2R3-S2; version=19.3 <19.3R2-S6, 19.3R3-S2; version=19.4 <19.4R1-S4, 19.4R2-S4, 19.4R3-S3; version=20.1 <20.1R2-S2, 20.1R3; version=20.2 <20.2R2-S3, 20.2R3; version=20.3 <20.3R2

Published CVSS scores

7.5Juniper NetworksCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo