CVE-2026-91253 in Solaris
Summary
by MITRE • 10/21/2026
Vulnerability in the Oracle Solaris product of Oracle Systems (component: Kernel). The supported version that is affected is 11.4. Easily exploitable vulnerability allows low privileged attacker with logon to the infrastructure where Oracle Solaris executes to compromise Oracle Solaris. Successful attacks of this vulnerability can result in takeover of Oracle Solaris. CVSS 3.1 Base Score 7.8 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
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Analysis
by VulDB Data Team • 10/21/2026
The identified vulnerability resides within the kernel component of Oracle Solaris version 11.4, representing a critical security flaw that compromises the foundational integrity of the operating system. As the kernel serves as the core interface between software and hardware resources, any compromise at this level grants an attacker complete control over the underlying infrastructure. The affected product is specifically supported in its 11.4 iteration, indicating that systems running this specific release are susceptible to exploitation unless appropriate patches or mitigations have been applied. This vulnerability highlights a significant weakness in the privilege separation mechanisms of the Solaris kernel architecture, allowing for escalation from user-level operations to full system dominance.
The technical nature of this flaw allows for easy exploitation by an attacker who possesses low privileges and has valid logon credentials on the target infrastructure. Unlike vulnerabilities that require complex conditions or high-privilege access, this issue can be triggered with minimal initial foothold requirements. The attack vector is classified as local (AV:L) with a low complexity requirement (AC:L), meaning that once an attacker gains basic user-level access to the system, they do not need sophisticated tools or rare environmental conditions to execute the exploit. Crucially, no user interaction (UI:N) is required for the successful execution of this attack vector, making it particularly dangerous in multi-user environments where unattended sessions or automated processes might inadvertently trigger the vulnerable code path.
The operational impact of a successful exploitation is severe, resulting in a complete takeover of Oracle Solaris. This aligns with the CVSS 3.1 base score of 7.8, which reflects high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H). When an attacker achieves kernel-level access through this vulnerability, they can bypass all standard security controls implemented at higher levels. They gain unrestricted read and write access to sensitive data stored on the system, allowing for extensive information disclosure that violates organizational privacy policies and regulatory compliance standards such as GDPR or HIPAA if applicable. Furthermore, the ability to modify system files enables persistent backdoors, rootkits, or ransomware deployment, effectively neutralizing the integrity of the entire platform. The availability impact suggests that attackers can also crash services or the entire operating system, leading to denial-of-service conditions for legitimate users and business operations.
From a classification perspective, this vulnerability is consistent with CWE-269 Improper Privilege Management or potentially CWE-787 Out-of-bounds Write if the flaw involves memory corruption within kernel structures. In terms of adversary tactics, it maps directly to MITRE ATT&CK technique T1068 Exploitation for Privilege Escalation and T1053 Scheduled Task/Job which may be used post-exploitation to maintain access. The local attack vector combined with low privilege requirements places this in the context of lateral movement scenarios where an attacker moves from a compromised user account to full system control, facilitating further infiltration into deeper network segments protected by perimeter defenses that assume internal trust boundaries based on user privileges.
Mitigation strategies must prioritize immediate patching through Oracle’s official update channels for Solaris 11.4. Organizations should verify the presence of relevant errata patches addressing kernel privilege escalation flaws. In addition to software updates, implementing strict access control policies is essential to reduce the attack surface. This includes enforcing least-privilege principles across all user accounts and ensuring that only authorized personnel have local login capabilities on critical infrastructure systems. Network segmentation can also help contain potential breaches by limiting lateral movement opportunities if a single host is compromised. Continuous monitoring for anomalous kernel-level activities using intrusion detection systems configured to detect privilege escalation attempts will provide an additional layer of defense against exploitation of this vulnerability while patching efforts are underway.