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Vulnerability · Published Feb 25, 2024 · Assigned by Linux

CVE-2021-46904net: hso: fix null-ptr-deref during tty device unregistration

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 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.3%top 82.7% 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: hso: fix null-ptr-deref during tty device unregistration Multiple ttys try to claim the same the minor number causing a double unregistration of the same device. The first unregistration succeeds but the next one results in a null-ptr-deref. The get_free_serial_index() function returns an available minor number but doesn't assign it immediately. The assignment is done by the caller later. But before this assignment, calls to get_free_serial_index() would return the same minor number. Fix this by modifying get_free_serial_index to assign the minor number immediately after one is found to be and rename it to obtain_minor() to better reflect what it does. Similary, rename set_serial_by_index() to release_minor() and modify it to free up the minor number of the given hso_serial. Every obtain_minor() should have corresponding release_minor() call.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.10.38-1DEBIAN-CVE-2021-46904
Debian:13linux5.10.38-1DEBIAN-CVE-2021-46904
Debian:14linux5.10.38-1DEBIAN-CVE-2021-46904
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-46904
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-46904
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-46904

Affected products (as reported)

VendorProductVersions
Linux Linux 72dc1c096c7051a48ab1dbb12f71976656b55eb5 – before a462067d7c8e6953a733bf5ade8db947b1bb544972dc1c096c7051a48ab1dbb12f71976656b55eb5 – before 145c89c441d27696961752bf51b323f347601bee72dc1c096c7051a48ab1dbb12f71976656b55eb5 – before caf5ac93b3b5d5fac032fc11fbea680e115421b472dc1c096c7051a48ab1dbb12f71976656b55eb5 – before 92028d7a31e55d53e41cff679156b9432cffcb3672dc1c096c7051a48ab1dbb12f71976656b55eb5 – before 4a2933c88399c0ebc738db39bbce3ae89786d72372dc1c096c7051a48ab1dbb12f71976656b55eb5 – before dc195928d7e4ec7b5cfc6cd10dc4c8d87a7c72ac72dc1c096c7051a48ab1dbb12f71976656b55eb5 – before 388d05f70f1ee0cac4a2068fd295072f1a44152a72dc1c096c7051a48ab1dbb12f71976656b55eb5 – before 8a12f8836145ffe37e9c8733dce18c22fb668b66
Linux Linux 2.6.27

References