CyberSecBulletin
CVE-2022-50185NVD status: Analyzed

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2022-50185 is a high-severity out-of-bounds write vulnerability in Linux, with a CVSS 3.1 base score of 7.8 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 ea73869df6ef386fc0feeb28ff66742ca835b18f, 1f341053852be76f82610ce47a505d930512f05c, db1a9add3f90ff1c641974d5bb910c16b87af4ef 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 0.3% 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 ea73869df6ef386fc0feeb28ff66742ca835b18f or 1f341053852be76f82610ce47a505d930512f05c or db1a9add3f90ff1c641974d5bb910c16b87af4ef or 8508d6d23a247c29792ce2fc0df3f3404d6a6a80, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.14.291 or 4.19.256 or 5.4.211 or 5.10.137, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux69e0b57a91adca2e3eb56ed4db39ab90f3ae1043 up to, but not including, ea73869df6ef386fc0feeb28ff66742ca835b18f; 69e0b57a91adca2e3eb56ed4db39ab90f3ae1043 up to, but not including, 1f341053852be76f82610ce47a505d930512f05c; 69e0b57a91adca2e3eb56ed4db39ab90f3ae1043 up to, but not including, db1a9add3f90ff1c641974d5bb910c16b87af4ef; 69e0b57a91adca2e3eb56ed4db39ab90f3ae1043 up to, but not including, 8508d6d23a247c29792ce2fc0df3f3404d6a6a80; 69e0b57a91adca2e3eb56ed4db39ab90f3ae1043 up to, but not including, deb603c5928e546609c0d5798e231d0205748943; 69e0b57a91adca2e3eb56ed4db39ab90f3ae1043 up to, but not including, 782e413e38dffd37cc85b08b1ccb982adb4a93ce; 69e0b57a91adca2e3eb56ed4db39ab90f3ae1043 up to, but not including, 9faff03617afeced1c4e5daa89e79b3906374342; 69e0b57a91adca2e3eb56ed4db39ab90f3ae1043 up to, but not including, 136f614931a2bb73616b292cf542da3a18daefd5; and 1 more rangesea73869df6ef386fc0feeb28ff66742ca835b18f, 1f341053852be76f82610ce47a505d930512f05c, db1a9add3f90ff1c641974d5bb910c16b87af4ef, 8508d6d23a247c29792ce2fc0df3f3404d6a6a80, deb603c5928e546609c0d5798e231d0205748943, 782e413e38dffd37cc85b08b1ccb982adb4a93ce
LinuxLinux Kernel3.11 up to, but not including, 4.14.291; 4.15 up to, but not including, 4.19.256; 4.20 up to, but not including, 5.4.211; 5.5 up to, but not including, 5.10.137; 5.11 up to, but not including, 5.15.61; 5.16 up to, but not including, 5.18.18; 5.19 up to, but not including, 5.19.24.14.291, 4.19.256, 5.4.211, 5.10.137, 5.15.61, 5.18.18

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
HighData or code can be modified at will.
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:H/A:H. Scored by NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: drm/radeon: fix potential buffer overflow in ni_set_mc_special_registers() The last case label can write two buffers 'mc_reg_address[j]' and 'mc_data[j]' with 'j' offset equal to SMC_NISLANDS_MC_REGISTER_ARRAY_SIZE since there are no checks for this value in both case labels after the last 'j++'. Instead of changing '>' to '>=' there, add the bounds check at the start of the second 'case' (the first one already has it). Also, remove redundant last checks for 'j' index bigger than array size. The expression is always false. Moreover, before or after the patch 'table->last' can be equal to SMC_NISLANDS_MC_REGISTER_ARRAY_SIZE and it seems it can be a valid value. Detected using the static analysis tool - Svace.

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

The underlying weakness: Out-of-bounds Write

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

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Out-of-bounds Write vulnerabilities (CWE-787)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Write vulnerabilities

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