CVE-2022-49838 is a vulnerability in the Linux kernel's SCTP (Stream Control Transmission Protocol) implementation. The issue arises from improper handling of the out_curr pointer in the SCTP stream's output queue. Specifically, when all fragment chunks of the current message are pruned (removed) via the sctp_prsctp_prune_unsent() function, the out_curr pointer is not cleared (set to NULL) as it should be. This leads to a use-after-free or list corruption scenario because subsequent operations assume out_curr is valid, but it actually points to an already dequeued or non-existent chunk. The vulnerability was reported due to a crash involving list_del corruption and a NULL next pointer, indicating memory corruption in the linked list management within the SCTP scheduler. The root cause is that sctp_sched_dequeue_done(), which normally clears out_curr after all fragments are dequeued, is not called during pruning, leaving out_curr dangling. The patch fixes this by explicitly setting out_curr to NULL when the last fragment chunk is pruned from the output queue. This vulnerability can cause kernel crashes (denial of service) and potentially memory corruption, which might be leveraged for privilege escalation or arbitrary code execution, although no known exploits are reported in the wild. The affected product is the Linux kernel, specifically versions identified by the commit hashes provided, indicating a recent or development branch. The SCTP protocol is used for reliable, message-oriented communication, often in telecom and certain enterprise environments. The vulnerability requires kernel-level access or the ability to send crafted SCTP packets to trigger the flaw. No CVSS score is assigned yet, and no known exploits are publicly available.

For European organizations, the impact of CVE-2022-49838 primarily involves potential denial of service due to kernel crashes on systems running vulnerable Linux kernels with SCTP enabled. Organizations relying on Linux servers for critical infrastructure, telecom services, or enterprise applications that utilize SCTP for communication could experience service interruptions. While no known exploits exist, the memory corruption risk could be escalated by threat actors to gain unauthorized privileges or execute arbitrary code, posing a significant security risk if exploited. This is particularly relevant for sectors such as telecommunications, financial services, and government agencies in Europe that deploy Linux-based systems for network infrastructure. The vulnerability could also impact cloud service providers and data centers operating Linux servers, potentially affecting availability and integrity of services. Given the kernel-level nature, exploitation could compromise confidentiality, integrity, and availability of affected systems. However, exploitation complexity is moderate as it requires specific SCTP traffic manipulation or local access. The absence of known exploits reduces immediate risk but warrants proactive patching to prevent future attacks.

European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2022-49838. Since the vulnerability resides in the SCTP implementation, organizations that do not use SCTP can consider disabling the SCTP module to reduce attack surface. For systems where SCTP is essential, ensure strict network controls to limit SCTP traffic to trusted sources only. Employ kernel hardening techniques such as SELinux or AppArmor to restrict kernel module interactions and reduce impact of potential exploitation. Monitor system logs for unusual SCTP-related kernel warnings or crashes that could indicate attempted exploitation. Additionally, conduct regular vulnerability assessments and penetration tests focusing on kernel-level vulnerabilities and SCTP protocol handling. For critical infrastructure, implement network segmentation to isolate vulnerable systems and reduce lateral movement risk. Maintain an up-to-date inventory of Linux kernel versions deployed across the organization to ensure timely patch management. Finally, collaborate with Linux distribution vendors and subscribe to security advisories to receive prompt updates on patches and mitigations.