CyberSecBulletin
CVE-2022-49738NVD status: Modified

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2022-49738 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions e5142a4935c1f15841d06047b8130078fc4d7b8f, 914e38f02a490dafd980ff0f39cccedc074deb29, 97ccfffcc061e54ce87e4a51a40e2e9cb0b7076a as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.2% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to e5142a4935c1f15841d06047b8130078fc4d7b8f or 914e38f02a490dafd980ff0f39cccedc074deb29 or 97ccfffcc061e54ce87e4a51a40e2e9cb0b7076a or 5b25035fb888cb2f78bf0b9c9f95b1dc54480d36, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.4.232 or 5.10.168 or 5.15.93 or 6.1.11, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux7a2af766af15887754f7f7a0869b4603b390876a up to, but not including, e5142a4935c1f15841d06047b8130078fc4d7b8f; 7a2af766af15887754f7f7a0869b4603b390876a up to, but not including, 914e38f02a490dafd980ff0f39cccedc074deb29; 7a2af766af15887754f7f7a0869b4603b390876a up to, but not including, 97ccfffcc061e54ce87e4a51a40e2e9cb0b7076a; 7a2af766af15887754f7f7a0869b4603b390876a up to, but not including, 5b25035fb888cb2f78bf0b9c9f95b1dc54480d36; 7a2af766af15887754f7f7a0869b4603b390876a up to, but not including, d3b7b4afd6b2c344eabf9cc26b8bfa903c164c7c; 4.14e5142a4935c1f15841d06047b8130078fc4d7b8f, 914e38f02a490dafd980ff0f39cccedc074deb29, 97ccfffcc061e54ce87e4a51a40e2e9cb0b7076a, 5b25035fb888cb2f78bf0b9c9f95b1dc54480d36, d3b7b4afd6b2c344eabf9cc26b8bfa903c164c7c
LinuxLinux Kernelbefore 5.4.232; 5.5 up to, but not including, 5.10.168; 5.11 up to, but not including, 5.15.93; 5.16 up to, but not including, 6.1.115.4.232, 5.10.168, 5.15.93, 6.1.11

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.1HighCNA
CVSS 3.17.1HighNVD
CVSS 3.17.1HighCISA (ADP)

Official description

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to do sanity check on i_extra_isize in is_alive() syzbot found a f2fs bug: BUG: KASAN: slab-out-of-bounds in data_blkaddr fs/f2fs/f2fs.h:2891 [inline] BUG: KASAN: slab-out-of-bounds in is_alive fs/f2fs/gc.c:1117 [inline] BUG: KASAN: slab-out-of-bounds in gc_data_segment fs/f2fs/gc.c:1520 [inline] BUG: KASAN: slab-out-of-bounds in do_garbage_collect+0x386a/0x3df0 fs/f2fs/gc.c:1734 Read of size 4 at addr ffff888076557568 by task kworker/u4:3/52 CPU: 1 PID: 52 Comm: kworker/u4:3 Not tainted 6.1.0-rc4-syzkaller-00362-gfef7fd48922d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:284 [inline] print_report+0x15e/0x45d mm/kasan/report.c:395 kasan_report+0xbb/0x1f0 mm/kasan/report.c:495 data_blkaddr fs/f2fs/f2fs.h:2891 [inline] is_alive fs/f2fs/gc.c:1117 [inline] gc_data_segment fs/f2fs/gc.c:1520 [inline] do_garbage_collect+0x386a/0x3df0 fs/f2fs/gc.c:1734 f2fs_gc+0x88c/0x20a0 fs/f2fs/gc.c:1831 f2fs_balance_fs+0x544/0x6b0 fs/f2fs/segment.c:410 f2fs_write_inode+0x57e/0xe20 fs/f2fs/inode.c:753 write_inode fs/fs-writeback.c:1440 [inline] __writeback_single_inode+0xcfc/0x1440 fs/fs-writeback.c:1652 writeback_sb_inodes+0x54d/0xf90 fs/fs-writeback.c:1870 wb_writeback+0x2c5/0xd70 fs/fs-writeback.c:2044 wb_do_writeback fs/fs-writeback.c:2187 [inline] wb_workfn+0x2dc/0x12f0 fs/fs-writeback.c:2227 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 The root cause is that we forgot to do sanity check on .i_extra_isize in below path, result in accessing invalid address later, fix it. - gc_data_segment - is_alive - data_blkaddr - offset_in_addr

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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