CyberSecBulletin
CVE-2022-50410NVD status: Modified

Linux: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2022-50410 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 2007867c5874134f2271eb276398208070049dd3, 2be9331ca6061bc6ea32247266f45b8b21030244, ea4c3eee0fd72fcedaa238556044825639cd3607 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 0.43% 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 2007867c5874134f2271eb276398208070049dd3 or 2be9331ca6061bc6ea32247266f45b8b21030244 or ea4c3eee0fd72fcedaa238556044825639cd3607 or 1868332032eccbab8c1878a0d918193058c0a905, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.220 or 5.15.75 or 5.19.17 or 6.0.3, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux4452435948424e5322c2a2fefbdc2cf3732cc45d up to, but not including, 2007867c5874134f2271eb276398208070049dd3; 4452435948424e5322c2a2fefbdc2cf3732cc45d up to, but not including, 2be9331ca6061bc6ea32247266f45b8b21030244; 4452435948424e5322c2a2fefbdc2cf3732cc45d up to, but not including, ea4c3eee0fd72fcedaa238556044825639cd3607; 4452435948424e5322c2a2fefbdc2cf3732cc45d up to, but not including, 1868332032eccbab8c1878a0d918193058c0a905; 4452435948424e5322c2a2fefbdc2cf3732cc45d up to, but not including, 401bc1f90874280a80b93f23be33a0e7e2d1f912; 2.6.192007867c5874134f2271eb276398208070049dd3, 2be9331ca6061bc6ea32247266f45b8b21030244, ea4c3eee0fd72fcedaa238556044825639cd3607, 1868332032eccbab8c1878a0d918193058c0a905, 401bc1f90874280a80b93f23be33a0e7e2d1f912
LinuxLinux Kernelbefore 5.10.220; 5.11 up to, but not including, 5.15.75; 5.16 up to, but not including, 5.19.17; 6.0 up to, but not including, 6.0.35.10.220, 5.15.75, 5.19.17, 6.0.3

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 3.19.8CriticalCNA
CVSS 3.17.8HighNVD
CVSS 3.17.8HighCISA (ADP)

Official description

In the Linux kernel, the following vulnerability has been resolved: NFSD: Protect against send buffer overflow in NFSv2 READ Since before the git era, NFSD has conserved the number of pages held by each nfsd thread by combining the RPC receive and send buffers into a single array of pages. This works because there are no cases where an operation needs a large RPC Call message and a large RPC Reply at the same time. Once an RPC Call has been received, svc_process() updates svc_rqst::rq_res to describe the part of rq_pages that can be used for constructing the Reply. This means that the send buffer (rq_res) shrinks when the received RPC record containing the RPC Call is large. A client can force this shrinkage on TCP by sending a correctly- formed RPC Call header contained in an RPC record that is excessively large. The full maximum payload size cannot be constructed in that case.

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

References

Recent Out-of-bounds Write vulnerabilities

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