In the Linux kernel, the following vulnerability has been resolved: ip6_vti: fix slab-use-after-free in decode_session6. This vulnerability allows slab-use-after-free to occur when the ipv6_vti device is set to the qdisc of the sfb type. During the enqueuing process, the cb field of the sent skb may be modified. As a result, when the ipv6_vti device sends IPv6 packets, it may lead to instability and potential crashes.
The severity level of this vulnerability is currently classified as unknown due to a lack of a CVSS score. However, organizations should remain aware of the implications and monitor for updates. Risk to organizations includes the possibility of system crashes or degraded performance if exploited.
As of now, there are no known exploits associated with this vulnerability, and it is not included in the Known Exploited Vulnerabilities (KEV) catalog. Organizations should prioritize monitoring their systems and applying any relevant updates once they become available.
Given the nature of the vulnerability, organizations should address in priority patch cycle as a precautionary measure to mitigate potential risks.
Vulnerability Details
The vulnerability is identified as CVE-2023-53821. It was published on December 9, 2025, with the last modification occurring on April 15, 2026. The vulnerability description specifically mentions a slab-use-after-free issue within the decode_session6 function. This function is responsible for handling IPv6 sessions within the Linux kernel.
The vulnerability affects the Linux kernel and is related to the handling of IPv6 packets. Although there are no specific version numbers mentioned in the CVE details, it is crucial for organizations using the Linux kernel to stay updated on any patches released in response to this issue.
Technical Analysis
The root cause of the issue lies in the handling of the cb field during the enqueuing of packets. When the ipv6_vti device is set to the sfb type, the cb field can be modified unexpectedly, leading to a slab-use-after-free scenario. This occurs when the memory previously allocated is freed while still being accessed, which can cause unpredictable behavior in the kernel.
The attack vector for this vulnerability is classified as unknown, and the attack complexity is considered low. No special privileges are required for exploitation, and user interaction is not necessary. If successfully exploited, the vulnerability may impact confidentiality, integrity, and availability, but specific impacts are currently unknown due to the lack of public exploit information.
Risk & Impact Analysis
Organizations utilizing the Linux kernel should be aware of the potential risks associated with this vulnerability. While the likelihood of exploitation is currently low, any vulnerability within the kernel can have far-reaching implications given its critical role in system operations. The vulnerability could lead to instability, impacting services relying on the kernel.
Risk to organizations includes potential system crashes or degradation in performance. Additionally, as this vulnerability remains unresolved, the longer it exists in the environment, the higher the potential for exploitation in the future. Therefore, organizations should address in priority patch cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
Currently, there are no specific versions listed as affected by this vulnerability. In absence of specific version information, organizations should consider all versions prior to the vendor patch.
Mitigation & Remediation
Organizations should monitor the Linux kernel for patches that address this vulnerability. Once a patch is released, organizations should apply it immediately to mitigate any risks associated with the vulnerability. Additionally, configuration hardening and network controls could further enhance security against potential exploitation.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor logs for unusual activity related to IPv6 packet handling. Additionally, behavioral anomalies in network traffic or system performance could indicate exploitation attempts.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability lies in its potential to expose systems to instability. As organizations increasingly rely on the Linux kernel, awareness and proactive measures become crucial. Security teams should learn from this incident to identify and address similar vulnerabilities promptly.
Security teams should also consider implementing a comprehensive vulnerability management program to ensure timely identification and remediation of vulnerabilities, as detailed in our vulnerability management program. Additionally, regular penetration testing can help surface similar weaknesses and improve overall security posture.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
.webp)