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CVE-2021-29256

From Exploited flaws, HARD’s guide to the flaws being used in attacks · Checked
This article is about a flaw in Arm Mali Graphics Processing Unit (GPU). For every flaw being used in attacks, see Exploited flaws; for Arm’s, see Arm flaws being used in attacks.

CVE-2021-29256 is a security flaw in Arm Mali Graphics Processing Unit (GPU), the graphics chip design in many Android phones. Someone who already has a foothold can use Arm Mali Graphics Processing Unit (GPU) to take full control of the machine. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 7 Jul 2023.[1]

Arm Mali Graphics Processing Unit (GPU) is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Arm has published a fix or advice.

Description

CISA calls it a mali GPU kernel driver use-after-free in Arm Mali Graphics Processing Unit (GPU). In its words: “Arm Mali GPU Kernel Driver contains a use-after-free vulnerability that may allow a non-privileged user to gain root privilege and/or disclose information.”[1]

The CVE record adds: “. 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.”[2]

The underlying weakness is use after free (CWE-416), in MITRE’s list of common software weaknesses.

It scores 8.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]

Affected versions

NVD’s record doesn’t list version ranges for it; Arm’s advisory has them[3]. CISA names the product as Arm Mali Graphics Processing Unit (GPU).

Every device with Arm Mali Graphics Processing Unit (GPU) needs the update.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 7 Jul 2023, 774 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 28 Jul 2023 to fix it.[1]

FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 3%. That’s in the top 13% of the flaws it scores.[4]

CISA assesses it as not automatable: each attack takes some work.

CISA doesn’t say who was attacked, or how.

Fix

Arm has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions or discontinue use of the product if updates are unavailable.”[1]

  1. Update Arm Mali Graphics Processing Unit (GPU) now.Install the latest update from Arm on every device that has it, and restart when asked. Then turn on automatic updates, so the next fix arrives on its own.
  2. If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.

Timeline

DateEvent
The flaw is made public in the National Vulnerability Database, with a severity score of 8.8.[2]
CISA adds it to its catalog of flaws known to be used in attacks.[1]
CISA’s deadline for US government agencies to fix it.[1]
FIRST puts the odds of it being used in attacks in the next 30 days at 3%.[4]

See also

Other Arm Mali Graphics Processing Unit (GPU) flaws

Other Arm flaws

  • CVE-2024-4610, Arm Mali GPU Kernel Driver: use-after-free ·
  • CVE-2023-4211, Arm Mali GPU Kernel Driver: use-after-free ·
  • CVE-2021-27562, Arm Trusted Firmware: out-of-bounds write ·

Other use after free flaws

  • CVE-2026-109619, PHP: stale internal request-state ·
  • CVE-2026-109618, PHP: memory corruption ·
  • CVE-2026-68820, Microsoft Windows Ancillary Function Driver for WinSock: use-after-free ·
  • CVE-2010-0249, Microsoft Internet Explorer: use-after-free ·
  • CVE-2020-9715, Adobe Acrobat: use-after-free ·

Every Arm flaw on CISA’s list · Everything added in July 2023

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “Arm Mali GPU Kernel Driver Use-After-Free Vulnerability”. Known Exploited Vulnerabilities Catalog, added 7 Jul 2023.
  2. ^ National Institute of Standards and Technology. “CVE-2021-29256 Detail”. National Vulnerability Database, published 24 May 2021.
  3. ^ Arm. Advisories and fixes: developer.arm.com, developer.arm.com.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.030, percentile 87.3, 31 Oct 2026.
  5. CVE Program. “CVE-2021-29256”. The official CVE record.

This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.