EUVD-2026-42697Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:D/RE:M/U:Green
Local access and high privileges required to modify SSH config hierarchy; impact is solely mgd availability with no scope change.
Primary rating from Vendor (juniper).
CVSS VectorVendor: juniper
Lifecycle Timeline
2DescriptionCVE.org
A NULL Pointer Dereference vulnerability in the management daemon (mgd) of Juniper Networks Junos OS and Junos OS Evolved allows a local, high-privileged attacker setting or deactivating a specific SSH configuration parameter to create a Denial of Service (DoS).
A local high-privileged user configuring or deactivating a specific 'system services ssh' configuration parameter can exploit a null pointer dereference in one of the functions used by SSH. The function attempts to dereference a null pointer when accessing certain configuration data, resulting in an mgd process crash and restart. Continued execution of these configuration commands will create a sustained Denial of Service (DoS) condition.
This issue affects: Junos OS:
- from 22.3 before 22.3R3-S5;
- from 22.4 before 22.4R3-S10;
- from 23.2 before 23.2R2-S7;
- from 23.4 before 23.4R2-S8.
This issue does not affect Junos OS before 22.3R1.
Junos OS Evolved:
- from 22.3R1-EVO before 23.2R2-S7-EVO;
- from 23.4 before 23.4R2-S8-EVO.
This issue does not affect Junos OS Evolved before 22.3R1-EVO.
AnalysisAI
NULL pointer dereference in the Juniper Networks Junos OS and Junos OS Evolved management daemon (mgd) allows a local, high-privileged attacker to crash the mgd process by manipulating a specific 'system services ssh' configuration parameter. Repeated execution of the offending configuration commands sustains the Denial of Service condition until the action ceases, as mgd will restart but crash again upon re-triggering. No public exploit code has been identified and this vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog; the attack barrier is high, requiring both local access and administrative-level credentials.
Technical ContextAI
The management daemon (mgd) is the core configuration processing component in Juniper's Junos OS and Junos OS Evolved - it handles all CLI-driven configuration commits and deactivations. The vulnerability (CWE-476: NULL Pointer Dereference) arises within an internal function invoked during SSH configuration processing under the 'system services ssh' hierarchy. When a specific parameter is set or deactivated, the function attempts to dereference a pointer that has not been initialized, resulting in a fatal process crash. Because mgd is the single management plane daemon, its crash disrupts device configurability and potentially in-band management access until the process restarts. The CVSS 4.0 vector confirms local attack vector (AV:L), no prior conditions required beyond the privilege level (AT:N), and exclusive availability impact (VA:H) with no confidentiality or integrity consequences. Affected CPE targets Junos OS versions 22.3 through 23.4 and Junos OS Evolved 22.3R1-EVO through 23.4, introduced with the 22.3R1 code branch.
RemediationAI
The primary remediation is upgrading to a fixed release: for Junos OS, upgrade to 22.3R3-S5, 22.4R3-S10, 23.2R2-S7, or 23.4R2-S8 (or later within each train); for Junos OS Evolved, upgrade to 23.2R2-S7-EVO or 23.4R2-S8-EVO (or later). Patch details and download links are available through the Juniper Support Portal at https://supportportal.juniper.net/JSA110072. As a compensating control where immediate patching is not possible, restrict CLI and NETCONF/RESTCONF access to the 'system services ssh' configuration stanza to the minimum number of trusted administrator accounts using Junos access controls or role-based access control (RBAC). Note that this reduces exposure but does not eliminate it, as any remaining administrator with access to the ssh hierarchy can still trigger the crash. Given the CVSS supplemental remediation tag R:A, automated patch delivery may be available through Juniper's update mechanisms - verify with your support contract.
named in ISC BIND 9.x before 9.9.8-P4 and 9.10.x before 9.10.3-P4 does not properly handle DNAME records when parsing fe
named in ISC BIND 9.x before 9.9.8-P4 and 9.10.x before 9.10.3-P4 allows remote attackers to cause a denial of service (
A PHP External Variable Modification vulnerability in J-Web of Juniper Networks Junos OS on EX Series and SRX Series all
jsdm/ajax/port.php in J-Web in Juniper Junos before 10.4R13, 11.4 before 11.4R7, 12.1 before 12.1R5, 12.2 before 12.2R3,
Juniper Junos 11.4 before R11, 12.1 before R9, 12.1X44 before D30, 12.1X45 before D20, 12.1X46 before D15, 12.1X47 befor
NFX Series devices using Juniper Networks Junos OS are susceptible to a local command execution vulnerability thereby al
NFX Series devices using Juniper Networks Junos OS are susceptible to a local code execution vulnerability thereby allow
Insufficient validation of environment variables in the telnet client supplied in Junos OS can lead to stack-based buffe
An Out-of-Bounds Write vulnerability in the H.323 ALG of Juniper Networks Junos OS allows an unauthenticated, network-ba
On QFX10000 Series devices using Juniper Networks Junos OS when configured as transit IP/MPLS penultimate hop popping (P
A Missing Release of Memory after Effective Lifetime vulnerability in the kernel of Juniper Networks Junos OS allows an
An Uncontrolled Memory Allocation vulnerability leading to a Heap-based Buffer Overflow in the packet forwarding engine
Same weakness CWE-476 – NULL Pointer Dereference
View allSame technique Denial Of Service
View allShare
External POC / Exploit Code
Leaving vuln.today