Juniper Junos OS Evolved prior 24.4R2-S3-EVO/25.2R2/25.2R2-EVO evo-aftmand state issue

Summaryinfo

A vulnerability was found in Juniper Junos OS Evolved. It has been rated as critical. The impacted element is an unknown function of the component evo-aftmand. Performing a manipulation results in state issue. This vulnerability is reported as CVE-2026-33794. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability classified as critical has been found in Juniper Junos OS Evolved. This affects an unknown function of the component evo-aftmand. The manipulation with an unknown input leads to a state issue vulnerability. CWE is classifying the issue as CWE-371. This is going to have an impact on availability. The summary by CVE is:

An Improper Check for Unusual or Exceptional Conditions vulnerability in the advanced forwarding toolkit (evo-aftmand) of Juniper Networks Junos OS Evolved on PTX Series allows an unauthenticated network-based attacker generating continuous routing updates, resulting in unilist ECMP routes, to crash the evo-aftmand process on the PFE, leading to a Denial-of-Service (DoS). The conditions required for successful exploitation are based on a sequence of events that are outside an attacker's direct control. Unified list (unilist) ECMP routes are a specific ECMP behavior where multiple equal-cost routes share a single logical next-hop list entry. The router treats them as one route with multiple next hops and load balances traffic across that unified list. Due to an issue processing unilist ECMP routing updates, internal state corruption may occur, especially in large-scale ECMP unilist deployments, leading to the evo-aftmand process crashing, resulting in an evo-aftmand-bx core. Manual intervention is required to recover by rebooting the system or restarting the FPC. This issue affects Junos OS Evolved on PTX : * from 24.4R2-EVO before 24.4R2-S3-EVO; * from 25.2 before 25.2R2-EVO.

It is possible to read the advisory at supportportal.juniper.net. This vulnerability is uniquely identified as CVE-2026-33794 since 03/23/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/09/2026).

Upgrading to version 24.4R2-S3-EVO, 25.2R2 or 25.2R2-EVO eliminates this vulnerability.

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Productinfo

Type

• Router Operating System

Vendor

• Juniper

Name

• Junos OS Evolved

License

• commercial

Website

• Vendor: https://www.juniper.net/

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