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Vulnerability · Published May 24, 2024 · Assigned by Linux

CVE-2021-47556ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce()

Medium 5.5

In plain English

A medium-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)5.5Medium
Exploit odds (30 days)0.2%top 91.9% 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: ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce() ethtool_set_coalesce() now uses both the .get_coalesce() and .set_coalesce() callbacks. But the check for their availability is buggy, so changing the coalesce settings on a device where the driver provides only _one_ of the callbacks results in a NULL pointer dereference instead of an -EOPNOTSUPP. Fix the condition so that the availability of both callbacks is ensured. This also matches the netlink code. Note that reproducing this requires some effort - it only affects the legacy ioctl path, and needs a specific combination of driver options: - have .get_coalesce() and .coalesce_supported but no .set_coalesce(), or - have .set_coalesce() but no .get_coalesce(). Here eg. ethtool doesn't cause the crash as it first attempts to call ethtool_get_coalesce() and bails out on error.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.15.15-1DEBIAN-CVE-2021-47556
Debian:13linux5.15.15-1DEBIAN-CVE-2021-47556
Debian:14linux5.15.15-1DEBIAN-CVE-2021-47556
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-47556
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-47556

Affected products (as reported)

VendorProductVersions
Linux Linux f3ccfda1931977b80267ba54070a1aeafa18f6ca – before abfdd9e2f0f9699015d72317f74154d3e53664e6f3ccfda1931977b80267ba54070a1aeafa18f6ca – before 0276af2176c78771da7f311621a25d7608045827
Linux Linux 5.15

References