NVD / CVE Program· CNA mitre

CVE-2021-29256: .

Noroxi assessment

Priority: This week (action score 66/100)

CISA has confirmed exploitation in the wild (Jul 7, 2023). Remediation deadline for US federal agencies: Jul 28, 2023.
Probability of exploitation in the next 30 days: 2.9% (FIRST EPSS); higher than 87.3% of all records.
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Don’t wait for the next maintenance window. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

. The Arm Mali GPU kernel driver allows an unprivileged user to achieve access to freed memory, leading to information disclosure or root privilege escalation. This affects Bifrost r16p0 through r29p0 before r30p0, Valhall r19p0 through r29p0 before r30p0, and Midgard r28p0 through r30p0.

HighCVSS 8.8 · v3.1KEVWeaponized No fix recorded

Memory safety

Published: May 24, 2021
Updated: Jun 16, 2026
EPSS: 2.9% · 87th percentile
CWE: CWE-416

Report tools

JSON

Action score

This week

Don’t wait for the next maintenance window.

CVSS: 35 / 40 · 8.8 / 10
CISA KEV: 30 / 30 · Listed
EPSS: 1 / 30 · 2.9%

CISA SSVC decision

Exploitation: active
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Jul 7, 2023. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Jul 28, 2023.

Get told when this record changes

In CISA KEV: exploitation in the wild confirmed
Weaponized exploit exists
No fixed version yet

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
arm	bifrost gpu kernel driver	cpe:2.3:a:arm:bifrost_gpu_kernel_driver
arm	midgard gpu kernel driver	cpe:2.3:a:arm:midgard_gpu_kernel_driver
arm	valhall gpu kernel driver	cpe:2.3:a:arm:valhall_gpu_kernel_driver

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

arm bifrost gpu kernel driverr16p0 and later · before r30p0
arm midgard gpu kernel driverr28p0 and later · before r31p0
arm valhall gpu kernel driverr19p0 and later · before r30p0

Same product

arm: all records

Other highest-scoring records for the same primary product.

CVE-2022-38181The Arm Mali GPU kernel driver allows unprivileged users to access freed memory because GPU memory operations are mishandled.KEV
71This week
CVE-2021-28663The Arm Mali GPU kernel driver allows privilege escalation or information disclosure because GPU memory operations are mishandled, leading tKEV
69This week
CVE-2021-28664The Arm Mali GPU kernel driver allows privilege escalation or a denial of service (memory corruption) because an unprivileged user can achieKEV
67This week

Published before and after this one in the same product

Later →CVE-2021-44828Jan 14, 2022 · Arm Mali GPU Kernel Driver (Midgard r26p0 through r30p0, Bifrost r0p0 through r34p0, and Valhall r19p0 through r34p0) allows a non-privilege
31Monitor
Later →CVE-2022-22706Mar 3, 2022 · Arm Mali GPU Kernel Driver allows a non-privileged user to achieve write access to read-only memory pages.KEV
61This week
Later →CVE-2022-28348May 18, 2022 · Arm Mali GPU Kernel Driver (Midgard r4p0 through r31p0, Bifrost r0p0 through r36p0 before r37p0, and Valhall r19p0 through r36p0 before r37p
39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedMay 24, 2021
CISA KEVJul 7, 2023+773 d
TodayNov 4, 2026+1990 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

ArmIntigriti · paid · up to $20,000

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

developer.arm.com/support/arm-security-updates/mali-gpu-kernel-driver

Show all references (1 more)

www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-29256

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records