Log in Start free

Vulnerability · Published Feb 26, 2025 · Assigned by Linux

CVE-2021-47646Revert "Revert "block, bfq: honor already-setup queue merges""

High 7.8

In plain English

A high-severity use-after-free 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 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.3%top 79.0% 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: Revert "Revert "block, bfq: honor already-setup queue merges"" A crash [1] happened to be triggered in conjunction with commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges"). The latter was then reverted by commit ebc69e897e17 ("Revert "block, bfq: honor already-setup queue merges""). Yet, the reverted commit was not the one introducing the bug. In fact, it actually triggered a UAF introduced by a different commit, and now fixed by commit d29bd41428cf ("block, bfq: reset last_bfqq_created on group change"). So, there is no point in keeping commit 2d52c58b9c9b ("block, bfq: honor already-setup queue merges") out. This commit restores it. [1] https://bugzilla.kernel.org/show_bug.cgi?id=214503

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.17.3-1DEBIAN-CVE-2021-47646
Debian:13linux5.17.3-1DEBIAN-CVE-2021-47646
Debian:14linux5.17.3-1DEBIAN-CVE-2021-47646
Ubuntu:22.04:LTSlinux5.15.0-37.39UBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-aws5.15.0-1011.14UBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-azure5.15.0-1010.12UBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-gcp5.15.0-1008.12UBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-gke5.15.0-1008.10UBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-ibm5.15.0-1007.8UBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1008.11UBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-kvm5.15.0-1010.11UBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-37.39UBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-oracle5.15.0-1009.12UBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-raspi5.15.0-1011.13UBUNTU-CVE-2021-47646
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-47646
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2021-47646

Affected products (as reported)

VendorProductVersions
Linux Linux 430a67f9d6169a7b3e328bceb2ef9542e4153c7c – before 65d8a737452e88f251fe5d925371de6d606df613430a67f9d6169a7b3e328bceb2ef9542e4153c7c – before abc2129e646af7b43025d90a071f83043f1ae76c430a67f9d6169a7b3e328bceb2ef9542e4153c7c – before 4083925bd6dc89216d156474a8076feec904e607430a67f9d6169a7b3e328bceb2ef9542e4153c7c – before 15729ff8143f8135b03988a100a19e66d7cb7ecd
Linux Linux 5.13

Weakness: CWE-416 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References