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Vulnerability · Published May 21, 2024 · Assigned by Linux

CVE-2021-47280drm: Fix use-after-free read in drm_getunique()

High 7.0

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)7.0High
Exploit odds (30 days)0.2%top 92.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: drm: Fix use-after-free read in drm_getunique() There is a time-of-check-to-time-of-use error in drm_getunique() due to retrieving file_priv->master prior to locking the device's master mutex. An example can be seen in the crash report of the use-after-free error found by Syzbot: https://syzkaller.appspot.com/bug?id=148d2f1dfac64af52ffd27b661981a540724f803 In the report, the master pointer was used after being freed. This is because another process had acquired the device's master mutex in drm_setmaster_ioctl(), then overwrote fpriv->master in drm_new_set_master(). The old value of fpriv->master was subsequently freed before the mutex was unlocked. To fix this, we lock the device's master mutex before retrieving the pointer from from fpriv->master. This patch passes the Syzbot reproducer test.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.10.46-1DEBIAN-CVE-2021-47280
Debian:13linux5.10.46-1DEBIAN-CVE-2021-47280
Debian:14linux5.10.46-1DEBIAN-CVE-2021-47280
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-47280
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-47280
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-47280

Affected products (as reported)

VendorProductVersions
Linux Linux 5acc614ac47465fee6375a9af4740f618830762d – before 17dab9326ff263c62dab1dbac4492e2938a049e45acc614ac47465fee6375a9af4740f618830762d – before 7d233ba700ceb593905ea82b42dadb4ec8ef85e95acc614ac47465fee6375a9af4740f618830762d – before b246b4c70c1250e7814f409b243000f9c0bf79a35acc614ac47465fee6375a9af4740f618830762d – before 491d52e0078860b33b6c14f0a7ac74ca1b603bd65acc614ac47465fee6375a9af4740f618830762d – before f773f8cccac13c7e7bbd9182e7996c727742488e5acc614ac47465fee6375a9af4740f618830762d – before b436acd1cf7fac0ba987abd22955d98025c80c2b
Linux Linux 4.11

References