Vulnerability · Published Apr 22, 2021 · Assigned by juniper

CVE-2021-0239Junos OS Evolved: Denial of Service due to receipt of specific genuine layer 2 frames.

Medium 6.5

In plain English

A medium-severity security flaw in Junos OS Evolved from Juniper Networks. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.4%top 67.7% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official description

In Juniper Networks Junos OS Evolved, receipt of a stream of specific genuine Layer 2 frames may cause the Advanced Forwarding Toolkit (AFT) manager process (Evo-aftmand), responsible for handling Route, Class-of-Service (CoS), Firewall operations within the packet forwarding engine (PFE) to crash and restart, leading to a Denial of Service (DoS) condition. By continuously sending this specific stream of genuine Layer 2 frames, an attacker can repeatedly crash the PFE, causing a sustained Denial of Service (DoS). This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R1-EVO. This issue does not affect Junos OS versions.

Affected products (as reported)

Vendor	Product	Versions
Juniper Networks	Junos OS Evolved	unspecified – before 20.4R1-EVO

Weakness: CWE-754 · Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://kb.juniper.net/JSA11134 x_refsource_MISC