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Vulnerability · Published May 21, 2024 · Assigned by Linux

CVE-2021-47342ext4: fix possible UAF when remounting r/o a mmp-protected file system

High 7.8

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 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)7.8High
Exploit odds (30 days)0.2%top 84.2% 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: ext4: fix possible UAF when remounting r/o a mmp-protected file system After commit 618f003199c6 ("ext4: fix memory leak in ext4_fill_super"), after the file system is remounted read-only, there is a race where the kmmpd thread can exit, causing sbi->s_mmp_tsk to point at freed memory, which the call to ext4_stop_mmpd() can trip over. Fix this by only allowing kmmpd() to exit when it is stopped via ext4_stop_mmpd(). Bug-Report-Link: <20210629143603.2166962-1-yebin10@huawei.com>

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.14.6-1DEBIAN-CVE-2021-47342
Debian:13linux5.14.6-1DEBIAN-CVE-2021-47342
Debian:14linux5.14.6-1DEBIAN-CVE-2021-47342
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-47342
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-47342
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-47342

Affected products (as reported)

VendorProductVersions
Linux Linux 5e4f5138bd8522ebe231a137682d3857209a2c07 – before b663890d854403e566169f7e90aed5cd6ff64f6beb7b40d9d3785f7a131fb0b1f89bb6efa46c1833 – before 7ed572cdf11081f8f9e07abd4bea56a3f2c4edbd618f003199c6188e01472b03cdbba227f1dc5f24 – before 61bb4a1c417e5b95d9edb4f887f131de32e419cbcecfdb9cf9a700d1037066173abac0617f6788df5.12.18 – before 5.13
Linux Linux 5.10.51 – before 5.10.77

References