Vulnerability · Published May 21, 2024 · Assigned by Linux
CVE-2021-47321watchdog: Fix possible use-after-free by calling del_timer_sync()
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 83.9% 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: watchdog: Fix possible use-after-free by calling del_timer_sync() This driver's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | bpftool | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-abi-stablelists | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-core | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-cross-headers | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-debug | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-debug-core | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-debug-devel | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-debug-modules | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-debug-modules-extra | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-devel | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-doc | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-headers | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-modules | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-modules-extra | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-rt | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-core | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-debug | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-debug-core | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-debug-devel | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-debug-kvm | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-debug-modules | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-debug-modules-extra | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-devel | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-kvm | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-modules | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-rt-modules-extra | 4.18.0-553.22.1.rt7.363.el8_10 | ALSA-2024:7001 |
| AlmaLinux:8 | kernel-tools | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-tools-libs | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-tools-libs-devel | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-zfcpdump | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-zfcpdump-core | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-zfcpdump-devel | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-zfcpdump-modules | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | kernel-zfcpdump-modules-extra | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | perf | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| AlmaLinux:8 | python3-perf | 4.18.0-553.22.1.el8_10 | ALSA-2024:7000 |
| Debian:12 | linux | 5.14.6-1 | DEBIAN-CVE-2021-47321 |
| Debian:13 | linux | 5.14.6-1 | DEBIAN-CVE-2021-47321 |
| Debian:14 | linux | 5.14.6-1 | DEBIAN-CVE-2021-47321 |
| Rocky Linux:8 | kernel | 0:4.18.0-553.22.1.el8_10 | RLSA-2024:7000 |
| Rocky Linux:8 | kernel-rt | 0:4.18.0-553.22.1.rt7.363.el8_10 | RLSA-2024:7001 |
| Ubuntu:22.04:LTS | linux-allwinner-5.19 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-aws-5.19 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-aws-6.2 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-azure-5.19 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-azure-6.2 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-azure-fde-5.19 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-azure-fde-6.2 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-gcp-5.19 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-gcp-6.2 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-hwe-5.19 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-hwe-6.2 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-intel-iot-realtime | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-lowlatency-hwe-5.19 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-lowlatency-hwe-6.2 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-nvidia-6.2 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-oem-5.17 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-oem-6.0 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-oem-6.1 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:24.04:LTS | linux-raspi-realtime | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-realtime | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-riscv | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-riscv-5.19 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-starfive-5.19 | no fix listed | UBUNTU-CVE-2021-47321 |
| Ubuntu:22.04:LTS | linux-starfive-6.2 | no fix listed | UBUNTU-CVE-2021-47321 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | 7c25f8c9f67708e6464d2221bc311cbd99e950dc – before 58606882ad8ec6c39e0f40344b922921ef94ab4d7c25f8c9f67708e6464d2221bc311cbd99e950dc – before ca96b8ea5e74956071154bdb456778cc3027e79f7c25f8c9f67708e6464d2221bc311cbd99e950dc – before 8bec568d7518b1504a602ed5376bb322e4dbb2707c25f8c9f67708e6464d2221bc311cbd99e950dc – before ecd620e0fb1ff7f78fdb593379b2e6938c99707a7c25f8c9f67708e6464d2221bc311cbd99e950dc – before db222f1477ad5692cd454709b714949807e5d1117c25f8c9f67708e6464d2221bc311cbd99e950dc – before 66ba9cf929b1c4fabf545bd4c18f6f64e23e46e47c25f8c9f67708e6464d2221bc311cbd99e950dc – before 4c05dac488a660fe2925c047ecb119e7afaaeb1e7c25f8c9f67708e6464d2221bc311cbd99e950dc – before 1a053c4d716898a53c2e31c574a70ea0c37044a3 |
| Linux | Linux | 4.3 |
References
- https://git.kernel.org/stable/c/58606882ad8ec6c39e0f40344b922921ef94ab4d
- https://git.kernel.org/stable/c/ca96b8ea5e74956071154bdb456778cc3027e79f
- https://git.kernel.org/stable/c/8bec568d7518b1504a602ed5376bb322e4dbb270
- https://git.kernel.org/stable/c/ecd620e0fb1ff7f78fdb593379b2e6938c99707a
- https://git.kernel.org/stable/c/db222f1477ad5692cd454709b714949807e5d111
- https://git.kernel.org/stable/c/66ba9cf929b1c4fabf545bd4c18f6f64e23e46e4
- https://git.kernel.org/stable/c/4c05dac488a660fe2925c047ecb119e7afaaeb1e
- https://git.kernel.org/stable/c/1a053c4d716898a53c2e31c574a70ea0c37044a3
- https://git.kernel.org/stable/c/d0212f095ab56672f6f36aabc605bda205e1e0bf