CyberSecBulletin
CVE-2022-49292NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2022-49292 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 a63af1baf0a5e11827db60e3127f87e437cab6e5, 0c4190b41a69990666b4000999e27f8f1b2a426b, 5ce74ff7059341d8b2f4d01c3383491df63d1898 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 0.28% 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 a63af1baf0a5e11827db60e3127f87e437cab6e5 or 0c4190b41a69990666b4000999e27f8f1b2a426b or 5ce74ff7059341d8b2f4d01c3383491df63d1898 or 7a40cbf3579a8e14849ba7ce46309c1992658d2b, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.19.237 or 5.4.188 or 5.10.109 or 5.15.32, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, a63af1baf0a5e11827db60e3127f87e437cab6e5; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 0c4190b41a69990666b4000999e27f8f1b2a426b; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 5ce74ff7059341d8b2f4d01c3383491df63d1898; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 7a40cbf3579a8e14849ba7ce46309c1992658d2b; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, fb08bf99195a87c798bc8ae1357337a981faeade; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, e74a069c6a7bb505f3ade141dddf85f4b0b5145a; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, efb6402c3c4a7c26d97c92d70186424097b6e366; 2.6.12a63af1baf0a5e11827db60e3127f87e437cab6e5, 0c4190b41a69990666b4000999e27f8f1b2a426b, 5ce74ff7059341d8b2f4d01c3383491df63d1898, 7a40cbf3579a8e14849ba7ce46309c1992658d2b, fb08bf99195a87c798bc8ae1357337a981faeade, e74a069c6a7bb505f3ade141dddf85f4b0b5145a
LinuxLinux Kernelbefore 4.19.237; 4.20 up to, but not including, 5.4.188; 5.5 up to, but not including, 5.10.109; 5.11 up to, but not including, 5.15.32; 5.16 up to, but not including, 5.16.18; 5.174.19.237, 5.4.188, 5.10.109, 5.15.32, 5.16.18

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.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: ALSA: oss: Fix PCM OSS buffer allocation overflow We've got syzbot reports hitting INT_MAX overflow at vmalloc() allocation that is called from snd_pcm_plug_alloc(). Although we apply the restrictions to input parameters, it's based only on the hw_params of the underlying PCM device. Since the PCM OSS layer allocates a temporary buffer for the data conversion, the size may become unexpectedly large when more channels or higher rates is given; in the reported case, it went over INT_MAX, hence it hits WARN_ON(). This patch is an attempt to avoid such an overflow and an allocation for too large buffers. First off, it adds the limit of 1MB as the upper bound for period bytes. This must be large enough for all use cases, and we really don't want to handle a larger temporary buffer than this size. The size check is performed at two places, where the original period bytes is calculated and where the plugin buffer size is calculated. In addition, the driver uses array_size() and array3_size() for multiplications to catch overflows for the converted period size and buffer bytes.

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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