CyberSecBulletin
CVE-2022-27239NVD status: Modified

Cifs-utils: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2022-27239 is a high-severity out-of-bounds write vulnerability in Cifs-utils from Samba, 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 version 6.15 as the first without the flaw, so updating Cifs-utils to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.58% 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 Cifs-utils to 6.15 or a later version.
  2. Read the advisory on bugzilla.samba.org for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
SambaCifs-utilsbefore 6.156.15
DebianDebian Linux9.0; 10.0; 11.0Not stated
SUSECaas Platform4.0Not stated
SUSEEnterprise Storage6.0; 7.0Not stated
SUSELinux Enterprise Point Of Service11.0Not stated
SUSELinux Enterprise Storage7.1Not stated
SUSEManager Proxy4.1; 4.2; 4.3Not stated
SUSEManager Retail Branch Server4.1; 4.2; 4.3Not stated
SUSEManager Server4.1; 4.2; 4.3Not stated
SUSEOpenstack Cloud8.0; 9.0Not stated
SUSEOpenstack Cloud Crowbar8.0; 9.0Not stated
SUSELinux Enterprise Desktop15Not stated
SUSELinux Enterprise High Performance Computing12.0; 15.0Not stated
SUSELinux Enterprise Micro5.2Not stated
SUSELinux Enterprise Real Time15.0Not stated
SUSELinux Enterprise Server11; 12; 15Not stated
SUSELinux Enterprise Software Development Kit12Not stated
HPHelion Openstack8.0Not stated
Fedora ProjectFedora34; 35; 36Not stated

Version data comes from NVD's product matching. 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 3.17.8HighNVD
CVSS 2.07.2HighNVD

Official description

In cifs-utils through 6.14, a stack-based buffer overflow when parsing the mount.cifs ip= command-line argument could lead to local attackers gaining root privileges.

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

Advisories

Patches and release notes

Third-party and government advisories

Recent Out-of-bounds Write vulnerabilities

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