title: Kernel: gsm multiplexing race condition leads to privilege escalation
description: A race condition was found in the GSM 0710 tty multiplexor in the Linux kernel. This issue occurs when two threads execute the GSMIOC_SETCONF ioctl on the same tty file descriptor with the gsm line discipline enabled, and can lead to a use-after-free problem on a struct gsm_dlci while restarting the gsm mux. This could allow a local unprivileged user to escalate their privileges on the system.
problem types: Use After Free
affected:
{
product: kernel
vendor: n/a
versions:
version: 6.5-rc7, status: unaffected
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel-rt
defaultStatus: affected
versions:
version: 0:4.18.0-513.24.1.rt7.326.el8_9, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:enterprise_linux:8::nfv, cpe:/a:redhat:enterprise_linux:8::realtime]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: affected
versions:
version: 0:4.18.0-513.24.1.el8_9, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/o:redhat:enterprise_linux:8::baseos, cpe:/a:redhat:enterprise_linux:8::crb]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8
collectionURL: https://access.redhat.com/downloads/content/package-browser/
defaultStatus: unaffected
packageName: kpatch-patch
cpe: cpe:/o:redhat:enterprise_linux:8::baseos
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8.6 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: affected
versions:
version: 0:4.18.0-372.93.1.el8_6, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/o:redhat:rhel_eus:8.6::baseos, cpe:/o:redhat:enterprise_linux:8::hypervisor, cpe:/a:redhat:rhel_eus:8.6::crb]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8.6 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
defaultStatus: unaffected
packageName: kpatch-patch
cpe: cpe:/o:redhat:rhel_eus:8.6::baseos
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9.0 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: affected
versions:
version: 0:5.14.0-70.93.2.el9_0, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:rhel_eus:9.0::appstream, cpe:/o:redhat:rhel_eus:9.0::baseos, cpe:/a:redhat:rhel_eus:9.0::crb]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9.0 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel-rt
defaultStatus: affected
versions:
version: 0:5.14.0-70.93.1.rt21.165.el9_0, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:rhel_eus:9.0::nfv, cpe:/a:redhat:rhel_eus:9.0::realtime]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9.0 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
defaultStatus: unaffected
packageName: kpatch-patch
cpe: cpe:/o:redhat:rhel_eus:9.0::baseos
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9.2 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: affected
versions:
version: 0:5.14.0-284.55.1.el9_2, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:rhel_eus:9.2::crb, cpe:/o:redhat:rhel_eus:9.2::baseos, cpe:/a:redhat:rhel_eus:9.2::appstream]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9.2 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel-rt
defaultStatus: affected
versions:
version: 0:5.14.0-284.55.1.rt14.340.el9_2, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/a:redhat:rhel_eus:9.2::realtime, cpe:/a:redhat:rhel_eus:9.2::nfv]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9.2 Extended Update Support
collectionURL: https://access.redhat.com/downloads/content/package-browser/
defaultStatus: unaffected
packageName: kpatch-patch
cpe: cpe:/o:redhat:rhel_eus:9.2::baseos
}
{
vendor: Red Hat
product: Red Hat Virtualization 4 for Red Hat Enterprise Linux 8
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: affected
versions:
version: 0:4.18.0-372.93.1.el8_6, lessThan: *, versionType: rpm, status: unaffected
cpe: [cpe:/o:redhat:rhel_eus:8.6::baseos, cpe:/o:redhat:enterprise_linux:8::hypervisor, cpe:/a:redhat:rhel_eus:8.6::crb]
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 6
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:6
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 7
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:7
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 7
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel-rt
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:7
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: affected
cpes: cpe:/o:redhat:enterprise_linux:9
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel-rt
defaultStatus: affected
cpes: cpe:/o:redhat:enterprise_linux:9
}
{
product: Fedora
vendor: Fedora
collectionURL: https://packages.fedoraproject.org/
packageName: kernel
defaultStatus: affected
}
metrics:
other: [
content: {'value': 'Important', 'namespace': 'https://access.redhat.com/security/updates/classification/'}
type: Red Hat severity rating
]
workarounds: This flaw can be mitigated by preventing the affected `n_gsm` kernel module from being loaded. For instructions on how to blacklist a kernel module, please see https://access.redhat.com/solutions/41278.