# CVE-2022-48870: linux: In the Linux kernel, the following vulnerability has been resolved:  tty: fix possible null-ptr-defer in spk_ttyio_re...

CVE-2022-48870 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-48870, released August 21, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-48870
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0025
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 21, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  tty: fix possible null-ptr-defer in spk_ttyio_release  Run the following tests on the qemu platform:  syzkaller:~# modprobe speakup_audptr  input: Speakup as /devices/virtual/input/input4  initialized device: /dev/synth, node (MAJOR 10, MINOR 125)  speakup 3.1.6: initialized  synth name on entry is: (null)  synth probe  spk_ttyio_initialise_ldisc failed because tty_kopen_exclusive returned failed (errno -16), then remove the module, we will get a null-ptr-defer problem, as follow:  syzkaller:~# modprobe -r speakup_audptr  releasing synth audptr  BUG: kernel NULL pointer dereference, address: 0000000000000080  #PF: supervisor write access in kernel mode  #PF: error_code(0x0002) - not-present page  PGD 0 P4D 0  Oops: 0002 [#1] PREEMPT SMP PTI  CPU: 2 PID: 204 Comm: modprobe Not tainted 6.1.0-rc6-dirty #1  RIP: 0010:mutex_lock+0x14/0x30  Call Trace:  <TASK>   spk_ttyio_release+0x19/0x70 [speakup]   synth_release.part.6+0xac/0xc0 [speakup]   synth_remove+0x56/0x60 [speakup]   __x64_sys_delete_module+0x156/0x250   ? fpregs_assert_state_consistent+0x1d/0x50   do_syscall_64+0x37/0x90   entry_SYSCALL_64_after_hwframe+0x63/0xcd  </TASK>  Modules linked in: speakup_audptr(-) speakup  Dumping ftrace buffer:  in_synth->dev was not initialized during modprobe, so we add check for in_synth->dev to fix this bug.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.8-1 | [DEBIAN-CVE-2022-48870](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48870.md) | Aug 21, 2024 |
| Linux | linux Debian 13.5 (trixie) | 6.1.8-1 | [DEBIAN-CVE-2022-48870](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48870.md) | Aug 21, 2024 |
| Linux | linux Debian 14 | 6.1.8-1 | [DEBIAN-CVE-2022-48870](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48870.md) | Aug 21, 2024 |

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