CVE-2021-31353

Published Oct 19, 2021

Last updated a year ago

CVSS high 7.5
Bgp

Overview

Description
An Improper Handling of Exceptional Conditions vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an attacker to inject a specific BGP update, causing the routing protocol daemon (RPD) to crash and restart, leading to a Denial of Service (DoS). Continued receipt and processing of the BGP update will create a sustained Denial of Service (DoS) condition. This issue affects very specific versions of Juniper Networks Junos OS: 19.3R3-S2; 19.4R3-S3; 20.2 versions 20.2R2-S3 and later, prior to 20.2R3-S2; 20.3 versions 20.3R2 and later, prior to 20.3R3; 20.4 versions 20.4R2 and later, prior to 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos OS 20.1 is not affected by this issue. This issue also affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-S3-EVO, 20.4R3-EVO; 21.1-EVO versions prior to 21.1R2-EVO; 21.2-EVO versions prior to 21.2R2-EVO.
Source
sirt@juniper.net
NVD status
Modified

Risk scores

CVSS 3.1

Type
Secondary
Base score
7.5
Impact score
3.6
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity
HIGH

CVSS 2.0

Type
Primary
Base score
5
Impact score
2.9
Exploitability score
10
Vector string
AV:N/AC:L/Au:N/C:N/I:N/A:P

Weaknesses

sirt@juniper.net
CWE-755
nvd@nist.gov
CWE-755

Social media

Hype score
Not currently trending

Configurations

Related CVEs

  1. Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability•CVE-2026-20127
  2. A Buffer Over-read vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). When an affected device receives a BGP update with a set of specific optional transitive attributes over an established peering session, rpd will crash and restart when attempting to advertise the received information to another peer. This issue can only happen if one or both of the BGP peers of the receiving session are non-4-byte-AS capable as determined from the advertised capabilities during BGP session establishment. Junos OS and Junos OS Evolved default behavior is 4-byte-AS capable unless this has been specifically disabled by configuring: [ protocols bgp ... disable-4byte-as ] Established BGP sessions can be checked by executing: show bgp neighbor <IP address> | match "4 byte AS" This issue affects: Junos OS:  * all versions before 22.4R3-S8, * 23.2 versions before 23.2R2-S5, * 23.4 versions before 23.4R2-S6, * 24.2 versions before 24.2R2-S2, * 24.4 versions before 24.4R2; Junos OS Evolved:  * all versions before 22.4R3-S8-EVO, * 23.2 versions before 23.2R2-S5-EVO, * 23.4 versions before 23.4R2-S6-EVO, * 24.2 versions before 24.2R2-S2-EVO, * 24.4 versions before 24.4R2-EVO.•CVE-2025-60003
  3. An Improper Check for Unusual or Exceptional Conditions vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network-based attacker to cause a Denial-Of-Service (DoS). When an affected system receives a specific BGP EVPN update message over an established BGP session, this causes an rpd crash and restart. A BGP EVPN configuration is not necessary to be vulnerable. If peers are not configured to send BGP EVPN updates to a vulnerable device, then this issue can't occur. This issue affects iBGP and eBGP, over IPv4 and IPv6. This issue affects: Junos OS: * 23.4 versions from 23.4R2-S3 before 23.4R2-S5, * 24.2 versions from 24.2R2 before 24.2R2-S1, * 24.4 versions before 24.4R1-S3, 24.4R2; Junos OS Evolved: * 23.4-EVO versions from 23.4R2-S2-EVO before 23.4R2-S5-EVO, * 24.2-EVO versions from 24.2R2-EVO before 24.2R2-S1-EVO, * 24.4-EVO versions before 24.4R1-S3-EVO, 24.4R2-EVO.•CVE-2025-60004
  4. A vulnerability in confederation implementation for the Border Gateway Protocol (BGP)&nbsp;in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to a memory corruption that occurs when a BGP update is created with an AS_CONFED_SEQUENCE attribute that has 255 autonomous system numbers (AS numbers). An attacker could exploit this vulnerability by sending a crafted BGP update message, or the network could be designed in such a manner that the AS_CONFED_SEQUENCE attribute grows to 255 AS numbers or more. A successful exploit could allow the attacker to cause memory corruption, which may cause the BGP process to restart, resulting in a DoS condition. To exploit this vulnerability, an attacker must control a BGP confederation speaker within the same autonomous system as the victim, or the network must be designed in such a manner that the AS_CONFED_SEQUENCE attribute grows to 255 AS numbers or more.•CVE-2025-20115
  5. The BGP daemon in Extreme Networks ExtremeXOS (aka EXOS) 30.7.1.1 allows an attacker (who is not on a directly connected network) to cause a denial of service (BGP session reset) because of BGP attribute error mishandling (for attribute 21 and 25). NOTE: the vendor disputes this because it is "evaluating support for RFC 7606 as a future feature" and believes that "customers that have chosen to not require or implement RFC 7606 have done so willingly and with knowledge of what is needed to defend against these types of attacks."•CVE-2023-40457

References

Sources include official advisories and independent security research.