CVE-2021-47162

This linux kernel vulnerability occurs in the TIPC (Transparent Inter-Process Communication) networking subsystem, specifically concerning how socket buffer (SKB) fragments are handled when reassembling messages. The issue arises when the network code attempts to append a new fragment to a head SKB's fragment list (frag_list). If this target list already contains socket buffers cloned from elsewhere—such as those created by pskb_copy() where reference counts are actively shared—appending new fragments directly to it can corrupt the list, leading to improper memory management and subsequent kernel crashes. Patched kernel versions resolve the vulnerability by explicitly linearizing the head socket buffer (skb_linearize) during message reassembly, ensuring that new fragments are processed safely without corrupting shared memory structures.

This vulnerability is rated as having a Low impact because the TIPC protocol is not loaded or configured by default on Red Hat Enterprise Linux systems. Exploitation requires the tipc kernel module to be actively loaded and processing fragmented network traffic, which limits exposure to non-standard environments utilizing this protocol. Under these conditions, an attacker could trigger improper buffer handling during message reassembly, resulting in a denial of service through a kernel crash without compromising data confidentiality or integrity.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.