CVE-2026-102082 in Junos OS
Summary
by MITRE • 10/14/2026
An Improper Handling of Missing Special Element vulnerability in the SSL plugin of Juniper Networks Junos OS on SRX Series allows a network-based, unauthenticated attacker to cause a Denial-of-Service (DoS).
This issue is will occur when 'ssl-proxy' is configured on SRX platforms and during a TLS session-resumption attempt a specifically malformed TLS message is received. This results in an invalid pointer access and PFE crash which causes a temporary loss of traffic forwarding until the PFE automatically recovers. The exact internal timing to trigger this issue is outside the attacker's direct control.This issue affects Junos OS on SRX Series:
* All versions before 23.2R2-S5; * 23.4 versions before 23.4R2-S5; * 24.2 versions before 24.2R2-S2; * 24.4 versions before 24.4R2.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified as an improper handling of missing special element within the SSL plugin of Juniper Networks Junos OS on SRX Series devices represents a significant security risk for organizations relying on these platforms for secure network infrastructure. This flaw specifically impacts environments where ssl-proxy functionality is enabled, which is common in deployments requiring deep packet inspection and TLS termination services. The core technical issue arises during the process of TLS session resumption, a mechanism designed to optimize performance by allowing clients to reuse previously established cryptographic contexts without performing full handshake procedures. When an attacker sends a specially crafted, malformed TLS message intended for session resumption, the software fails to properly validate or handle missing critical elements within that message structure. This oversight leads directly to invalid pointer access within the Packet Forwarding Engine (PFE), triggering a crash of this essential component responsible for high-speed data plane operations.
From an operational perspective, the immediate consequence of this vulnerability is a Denial-of-Service condition characterized by a temporary loss of traffic forwarding capabilities. Because the PFE crashes upon encountering the malformed input, the device cannot process or forward network packets effectively until it undergoes automatic recovery procedures. While the system eventually restores functionality through self-healing mechanisms inherent in modern routing platforms, the interim period results in service disruption for connected users and services. The attacker does not require authentication to exploit this flaw, making it a remote attack vector accessible over the network without prior credentials or access privileges. Furthermore, the exact internal timing required to trigger the crash is outside the direct control of the attacker, suggesting that successful exploitation may depend on specific state conditions within the SSL session management logic rather than simple brute-force repetition.
This vulnerability aligns with CWE-20 Improper Input Validation and CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer, as it involves both inadequate checking of incoming data structures and subsequent memory corruption leading to application instability. In terms of offensive security frameworks such as MITRE ATT&CK, this exploit falls under Tactic TA0004 Impact due to its Denial-of-Service nature, specifically mapping to techniques like T1499 Endpoint Denial of Service or potentially T1529 System Shutdown/Reboot if the crash leads to a full device reboot. The ability for an unauthenticated remote actor to disrupt critical network infrastructure highlights the importance of securing management planes and data plane processing engines against malformed protocol messages, particularly in high-throughput environments where SSL inspection is active.
Mitigation strategies primarily involve upgrading Junos OS to patched versions that address this logic error within the SSL plugin. Affected systems running all versions prior to 23.2R2-S5, 23.4 versions before 23.4R2-S5, 24.2 versions before 24.2R2-S2, and 24.4 versions before 24.4R2 are vulnerable and require immediate attention to the latest stable release that includes the fix. In addition to software updates, network administrators should consider implementing strict access control lists on interfaces exposed to untrusted networks where ssl-proxy is enabled, limiting exposure to potential attackers who might attempt to send malformed TLS packets. Deploying intrusion prevention systems capable of detecting anomalous TLS handshake patterns can also provide an additional layer of defense by blocking suspicious traffic before it reaches the vulnerable Junos OS components, thereby reducing the attack surface and protecting service availability against this specific denial-of-service vector.