CyberSecBulletin
CVE-2021-28664Exploited in the wildNVD status: Analyzed

Arm Mali Graphics Processing Unit (GPU) Unspecified

Published Updated By the CyberSecBulletin desk

CVE-2021-28664 is a high-severity out-of-bounds write vulnerability in Bifrost GPU Kernel Driver from Arm, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version r29p0 as the first without the flaw, so updating Bifrost GPU Kernel Driver to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Bifrost GPU Kernel Driver to r29p0 or a later version.
  2. Update Midgard GPU Kernel Driver to r31p0 or a later version.
  3. Update Valhall GPU Kernel Driver to r29p0 or a later version.
  4. CISA's required action: Apply updates per vendor instructions.
  5. Read the advisory on developer.arm.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
ArmBifrost GPU Kernel Driverr0p0 up to, but not including, r29p0r29p0
ArmMidgard GPU Kernel Driverr8p0 up to, but not including, r31p0r31p0
ArmValhall GPU Kernel Driverr19p0 up to, but not including, r29p0r29p0

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
NetworkCan be exploited remotely over a network, including the internet.
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:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.8HighNVD
CVSS 3.18.8HighCISA (ADP)
CVSS 2.09.0HighNVD

Official description

The Arm Mali GPU kernel driver allows privilege escalation or a denial of service (memory corruption) because an unprivileged user can achieve read/write access to read-only pages. This affects Bifrost r0p0 through r29p0 before r30p0, Valhall r19p0 through r29p0 before r30p0, and Midgard r8p0 through r30p0 before r31p0.

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. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
  5. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in Bifrost GPU Kernel Driver

All Bifrost GPU Kernel Driver vulnerabilities

Recent Out-of-bounds Write vulnerabilities

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