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Juniper disclosed CVE-2026-21902, a critical remote code execution vulnerability in Junos OS Evolved affecting PTX Series routers. The issue is an incorrect permission assignment for a critical resource in the On-Box Anomaly Detection framework; if the service is reachable over the network, an unauthenticated attacker can execute code as root, enabling full device takeover. The service is described as running as root and being enabled by default, increasing impact where exposure exists.
watchTowr researchers reported the flaw and published technical analysis indicating the affected framework is intended for internal process communication and “should only be reachable” via internal interfaces, but may become accessible depending on configuration. Juniper advised customers to restrict/filter access (e.g., via firewall rules or ACLs) and indicated a patch would follow; impacted releases called out include 25.4R1-S1-EVO and 25.4R2-EVO, while non-Evolved Junos OS releases prior to 25.4R1-EVO were reported as not impacted. Juniper stated it had no evidence of active exploitation at the time of disclosure.
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watchTowr Labs published a detailed analysis showing that the exposed On-Box Anomaly Detection service listens on TCP port 8160, runs as root, and can be abused to create commands and DAGs that lead to shell execution via subprocess.run with shell=True. The publication also referenced proof-of-concept and detection artifact tooling for validation and artifact creation.
Juniper disclosed CVE-2026-21902 as a critical vulnerability affecting Junos OS Evolved 25.4R1-S1-EVO and 25.4R2-EVO on PTX routers. The company said it had not observed exploitation in the wild and advised customers to restrict access with ACLs or firewalls while a patch was being developed.
watchTowr researchers identified and reported CVE-2026-21902 to Juniper Networks. The flaw affects the On-Box Anomaly Detection framework in Junos OS Evolved on PTX Series routers and can enable unauthenticated remote code execution as root.
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Juniper disclosed a **critical remote code execution** vulnerability in **Junos OS Evolved** running on **PTX Series** routers that can allow an **unauthenticated, network-based attacker** to execute code as **root** and potentially take full control of affected devices (**CVE-2026-21902**). The flaw stems from **incorrect permission assignment** in the *On-Box Anomaly Detection* framework, which is intended to be reachable only by internal processes over an internal routing instance but is exposed via an externally reachable port; the vulnerable service runs as **root** and is **enabled by default**. Affected versions are **25.4** releases prior to **`25.4R1-S1-EVO`** and **`25.4R2-EVO`** on PTX Series; **standard (non-Evolved) Junos OS** and Junos OS Evolved versions before **`25.4R1-EVO`** are not impacted. Juniper released fixes in **`25.4R1-S1-EVO`**, **`25.4R2-EVO`**, and **`26.2R1-EVO`**, and at the time of advisory publication stated it was **not aware of active exploitation**; guidance includes prioritizing patching and, where immediate updates are not possible, restricting access to the exposed endpoints using **firewall filters/ACLs**. The Canadian Centre for Cyber Security echoed the vendor advisory and urged administrators to apply the updates.
Jun 29, 2026
Juniper Networks disclosed multiple high-severity vulnerabilities in **Junos OS** and **SRX/MX** platforms, including remotely exploitable denial-of-service flaws and local privilege-escalation issues. The most exposed bugs include **`CVE-2026-33790`**, which lets an unauthenticated attacker crash the `srxpfe` packet forwarding engine on **SRX Series** firewalls by sending a malformed **ICMPv6** packet to devices with **NAT64** enabled, and **`CVE-2026-33778`**, which allows a malformed initial **ISAKMP** packet to crash the `kmd` or `iked` daemons on **SRX** and **MX** systems providing IPsec VPN services. Juniper said repeated exploitation can sustain outages by forcing affected processes into crash loops, and that fixes were released through security bulletins including **`JSA107874`** and **`JSA107868`**. Juniper also fixed **`CVE-2026-33785`**, a missing authorization flaw in **MX Series** routers that allows any locally authenticated user to run privileged `request csds` commands and potentially compromise managed infrastructure in **JDM/CSDS** deployments, and **`CVE-2026-21916`**, a symlink-handling bug in the Junos CLI that can let a low-privileged user gain **root** when another user performs a configuration commit. Affected versions span several supported Junos release trains, with fixes issued on April 8, 2026; some older branches, including certain end-of-life releases, do not have patches. Detection guidance from Juniper and Tenable relies largely on version auditing, configuration review for exposed features such as NAT64 and IPsec, and monitoring for daemon crashes, suspicious `file link` activity, unexpected root access, and abuse of privileged management commands.
Jun 29, 2026
Juniper disclosed two denial-of-service vulnerabilities in **Junos OS Evolved** affecting **PTX Series** routers, with one issue also impacting the **QFX5000 Series**. The first flaw, tracked as **`CVE-2025-59969`**, allows an attacker to send crafted multicast packets that cause the `evo-aftmand` and `evo-pfemand` processes to crash and restart, disrupting forwarding-related functions on affected devices. A second vulnerability, **`CVE-2026-33783`**, affects PTX systems where **SR-TE tunnels provisioned via PCEP** are present; under those conditions, specific **gRPC** queries can trigger a crash in the `evo-aftman` process. Together, the advisories describe service instability risks in carrier-grade routing platforms, with crashes tied to malformed network traffic and management-plane queries rather than code execution.
Apr 9, 2026