CVE-2023-53485

A vulnerability has been identified in the Linux kernel component for the journaled file system (JFS) within the function dbAllocDmapLev(). Specifically, the leafidx variable can become negative, and then the code uses it in an array index operation dp->tree.stree[leafidx + LEAFIND] leading to damage of system availability

A moderate severity out-of-bounds array access was found in the Linux kernel's JFS file system code. In dbAllocDmapLev(), a negative leafidx value can be used to index dp->tree.stree[leafidx + LEAFIND], triggering an out-of-bounds access reported by UBSAN. The flaw is reachable through local file operations such as file creation on a JFS file system, as reported by syzkaller, and primarily compromises system availability by crashing the kernel. Because triggering the flaw requires the ability to perform file operations on a JFS file system of an affected system, Red Hat assesses the impact as Moderate, while NIST and the CVE.org record assign a higher score of 7.8 (Important). No actively supported Red Hat product is affected: the vulnerable code is not present in the Red Hat Enterprise Linux 7, 8, 9, and 10 kernel and kernel-rt streams, nor in Red Hat In-Vehicle OS. The remaining Red Hat Enterprise Linux 6 Extended Lifecycle Support stream is out of support scope, so the residual risk is limited to out-of-support systems using a JFS file system.

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.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.