In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix use-after-free bug in cifsdebugdataprocshow()
Skip SMB sessions that are being teared down (e.g. @ses->sesstatus == SESEXITING) in cifsdebugdataprocshow() to avoid use-after-free in @ses.
This fixes the following GPF when reading from /proc/fs/cifs/DebugData while mounting and umounting
[ 816.251274] general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6d81: 0000 [#1] PREEMPT SMP NOPTI ... [ 816.260138] Call Trace: [ 816.260329] <TASK> [ 816.260499] ? dieaddr+0x36/0x90 [ 816.260762] ? excgeneralprotection+0x1b3/0x410 [ 816.261126] ? asmexcgeneralprotection+0x26/0x30 [ 816.261502] ? cifsdebugtcon+0xbd/0x240 [cifs] [ 816.261878] ? cifsdebugtcon+0xab/0x240 [cifs] [ 816.262249] cifsdebugdataprocshow+0x516/0xdb0 [cifs] [ 816.262689] ? seqreaditer+0x379/0x470 [ 816.262995] seqreaditer+0x118/0x470 [ 816.263291] procregreaditer+0x53/0x90 [ 816.263596] ? srsoaliasreturnthunk+0x5/0x7f [ 816.263945] vfsread+0x201/0x350 [ 816.264211] ksysread+0x75/0x100 [ 816.264472] dosyscall64+0x3f/0x90 [ 816.264750] entrySYSCALL64afterhwframe+0x6e/0xd8 [ 816.265135] RIP: 0033:0x7fd5e669d381