CVE-2023-35788: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-35788 is a vulnerability discovered in the Linux kernel's Flower classifier (NETCLSFLOWER) before version 6.3.7. The vulnerability was identified by Hangyu Hua and disclosed in June 2023. It affects the flsetgeneveopt function in net/sched/clsflower.c, allowing an out-of-bounds write in the flower classifier code via TCAFLOWERKEYENCOPTS_GENEVE packets (Kernel Patch, NVD).

The vulnerability stems from an off-by-one error in the flsetgeneveopt function. When sending two TCAFLOWERKEYENCOPTSGENEVE packets with a total size of 252 bytes (key->encopts.len = 252), a third packet can bypass the bounds check and cause an out-of-bounds write at key->encopts.data[257]. The vulnerability has been assigned a CVSS v3.1 base score of 7.8 (High) with vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (NVD, OSS Security).

Successful exploitation of this vulnerability could result in denial of service (system crash) or privilege escalation, potentially allowing attackers to execute arbitrary code with elevated privileges (Debian Security, NetApp Advisory).

The vulnerability has been fixed in Linux kernel version 6.3.7 with a patch that adds additional bounds checking in the flsetgeneve_opt function. Various Linux distributions have backported the fix to their supported kernel versions. Users are advised to update their systems to the patched versions (Kernel Patch, Debian Security).