#VU49555 Access of Uninitialized Pointer

Published: 2021-01-15

Vulnerability identifier: #VU49555

Vulnerability risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-0209


Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Junos OS Evolved
Operating systems & Components / Operating system



The vulnerability allows a remote attacker to perform a DoS attack.

The vulnerability exists due to access to an uninitialized pointer in Regular expressions (REGEX) engine when processing valid BGP update packets from BGP peers. A remote attacker can certain valid BGP update packets and perform a denial of service (DoS) attack.


Install updates from vendor's website.

Juniper Networks Junos OS Evolved

  • 19.4 versions prior to 19.4R2-S2-EVO;
  • 20.1 versions prior to 20.1R1-S2-EVO, 20.1R2-S1-EVO.

Vulnerable software versions

Junos OS Evolved: before 19.4R2-S2-EVO, 20.1R1-S2-EVO, 20.1R2-S1-EVO, 20.2R1-EVO


External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

Latest bulletins with this vulnerability