CyberSecBulletin
CVE-2022-50478NVD status: Analyzed

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2022-50478 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 6b0ea3df56cccd53398d0289f399f19d43136b2e, a6f89b10042baca218c8598d6db5a44c7e32625f, 9b3ba54025357440d6c4414c670984f628c6f6bf 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 0.17% 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 6b0ea3df56cccd53398d0289f399f19d43136b2e or a6f89b10042baca218c8598d6db5a44c7e32625f or 9b3ba54025357440d6c4414c670984f628c6f6bf or d706485dffbbbf848e681edda29c7a46ac55698c, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.9.337 or 4.14.303 or 4.19.270 or 5.4.229, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxe339ad31f59925b48a92ee3947692fdf9758b8c7 up to, but not including, 6b0ea3df56cccd53398d0289f399f19d43136b2e; e339ad31f59925b48a92ee3947692fdf9758b8c7 up to, but not including, a6f89b10042baca218c8598d6db5a44c7e32625f; e339ad31f59925b48a92ee3947692fdf9758b8c7 up to, but not including, 9b3ba54025357440d6c4414c670984f628c6f6bf; e339ad31f59925b48a92ee3947692fdf9758b8c7 up to, but not including, d706485dffbbbf848e681edda29c7a46ac55698c; e339ad31f59925b48a92ee3947692fdf9758b8c7 up to, but not including, d464b035c0613856d012cf1704879d3ff3f057fb; e339ad31f59925b48a92ee3947692fdf9758b8c7 up to, but not including, b47f5c579c8186f7f5ab5e4254e0734ea5b7bf7a; e339ad31f59925b48a92ee3947692fdf9758b8c7 up to, but not including, 1012ff77284e3bec0ec0a35a820b03ec43dec2cc; e339ad31f59925b48a92ee3947692fdf9758b8c7 up to, but not including, 62d11ec205ef14d8acf172cfc9904fdbf200025a; and 2 more ranges6b0ea3df56cccd53398d0289f399f19d43136b2e, a6f89b10042baca218c8598d6db5a44c7e32625f, 9b3ba54025357440d6c4414c670984f628c6f6bf, d706485dffbbbf848e681edda29c7a46ac55698c, d464b035c0613856d012cf1704879d3ff3f057fb, b47f5c579c8186f7f5ab5e4254e0734ea5b7bf7a
LinuxLinux Kernel2.6.30 up to, but not including, 4.9.337; 4.10 up to, but not including, 4.14.303; 4.15 up to, but not including, 4.19.270; 4.20 up to, but not including, 5.4.229; 5.5 up to, but not including, 5.10.163; 5.11 up to, but not including, 5.15.86; 5.16 up to, but not including, 6.0.16; 6.1 up to, but not including, 6.1.24.9.337, 4.14.303, 4.19.270, 5.4.229, 5.10.163, 5.15.86

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.

Official description

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix shift-out-of-bounds/overflow in nilfs_sb2_bad_offset() Patch series "nilfs2: fix UBSAN shift-out-of-bounds warnings on mount time". The first patch fixes a bug reported by syzbot, and the second one fixes the remaining bug of the same kind. Although they are triggered by the same super block data anomaly, I divided it into the above two because the details of the issues and how to fix it are different. Both are required to eliminate the shift-out-of-bounds issues at mount time. This patch (of 2): If the block size exponent information written in an on-disk superblock is corrupted, nilfs_sb2_bad_offset helper function can trigger shift-out-of-bounds warning followed by a kernel panic (if panic_on_warn is set): shift exponent 38983 is too large for 64-bit type 'unsigned long long' Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106 ubsan_epilogue lib/ubsan.c:151 [inline] __ubsan_handle_shift_out_of_bounds+0x33d/0x3b0 lib/ubsan.c:322 nilfs_sb2_bad_offset fs/nilfs2/the_nilfs.c:449 [inline] nilfs_load_super_block+0xdf5/0xe00 fs/nilfs2/the_nilfs.c:523 init_nilfs+0xb7/0x7d0 fs/nilfs2/the_nilfs.c:577 nilfs_fill_super+0xb1/0x5d0 fs/nilfs2/super.c:1047 nilfs_mount+0x613/0x9b0 fs/nilfs2/super.c:1317 ... In addition, since nilfs_sb2_bad_offset() performs multiplication without considering the upper bound, the computation may overflow if the disk layout parameters are not normal. This fixes these issues by inserting preliminary sanity checks for those parameters and by converting the comparison from one involving multiplication and left bit-shifting to one using division and right bit-shifting.

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. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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