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Vulnerability · Published May 21, 2024 · Assigned by Linux

CVE-2021-47293net/sched: act_skbmod: Skip non-Ethernet packets

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 14% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)7.8High
Exploit odds (30 days)0.2%top 85.6% 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: net/sched: act_skbmod: Skip non-Ethernet packets Currently tcf_skbmod_act() assumes that packets use Ethernet as their L2 protocol, which is not always the case. As an example, for CAN devices: $ ip link add dev vcan0 type vcan $ ip link set up vcan0 $ tc qdisc add dev vcan0 root handle 1: htb $ tc filter add dev vcan0 parent 1: protocol ip prio 10 \ matchall action skbmod swap mac Doing the above silently corrupts all the packets. Do not perform skbmod actions for non-Ethernet packets.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.14.6-1DEBIAN-CVE-2021-47293
Debian:13linux5.14.6-1DEBIAN-CVE-2021-47293
Debian:14linux5.14.6-1DEBIAN-CVE-2021-47293
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-47293
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-47293
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-47293

Affected products (as reported)

VendorProductVersions
Linux Linux 86da71b57383d40993cb90baafb3735cffe5d800 – before e4fdca366806f6bab374d1a95e626a10a3854b0c86da71b57383d40993cb90baafb3735cffe5d800 – before a88414fb1117f2fe65fb88e45ba694e1d09d502486da71b57383d40993cb90baafb3735cffe5d800 – before 071729150be9e1d1b851b70efb6d91ee9269d57b86da71b57383d40993cb90baafb3735cffe5d800 – before 34f1e1f657fae2891b485a3b2b95fe4d2aef9f0d86da71b57383d40993cb90baafb3735cffe5d800 – before 727d6a8b7ef3d25080fad228b2c4a1d4da5999c6
Linux Linux 4.9

References