CVE-2023-6546: Kernel: gsm multiplexing race condition leads to privilege escalation
A race condition was found in the GSM 0710 tty multiplexor (drivers/tty/ngsm.c) in the Linux kernel. The flaw occurs when two threads execute the GSMIOCSETCONF ioctl on the same tty file descriptor with the gsm line discipline enabled and leads to a use-after-free on a struct gsmdlci while restarting the gsm mux. A local unprivileged user could use this vulnerability to escalate their privileges on the system.
ZDI Security Advisory: https://www.zerodayinitiative.com/advisories/ZDI-CAN-20527
Upstream fix: https://github.com/torvalds/linux/commit/3c4f8333b582487a2d1e02171f1465531cde53e3
Other sources
A race condition was found in the GSM 0710 tty multiplexor in the Linux kernel. This issue occurs when two threads execute the GSMIOCSETCONF 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 gsmdlci while restarting the gsm mux. This could allow a local unprivileged user to escalate their privileges on the system.
— NVD
Linux Kernel could allow a local authenticated attacker to gain elevated privileges on the system, caused by a race condition in the GSM 0710 tty multiplexor. By sending a specially crafted request, an authenticated attacker could exploit this vulnerability to gain elevated privileges.
— IBM
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 6.5 - Upgrade
Upgrade
linux kernel (drivers/tty/n_gsm.c)to a version that resolves this vulnerability.Patch ZDI-CAN-20527 - Upgrade
Upgrade
linux kernelto a version that resolves this vulnerability.Patch 3c4f8333b582487a2d1e02171f1465531cde53e3
Event History
Frequently Asked Questions
What is the severity of CVE-2023-6546?
CVE-2023-6546 has been categorized as a high-severity vulnerability due to its potential to cause a use-after-free condition.
How do I fix CVE-2023-6546?
To remediate CVE-2023-6546, ensure that you upgrade to a patched version of the Linux kernel or the affected software that addresses this flaw.
Which systems are affected by CVE-2023-6546?
CVE-2023-6546 affects several Linux kernel versions up to 6.5, as well as specific versions of IBM QRadar SIEM and Red Hat Enterprise Linux.
What type of vulnerability is CVE-2023-6546?
CVE-2023-6546 is classified as a race condition vulnerability that leads to a use-after-free error in the Linux kernel.
Can CVE-2023-6546 be exploited remotely?
Exploitation of CVE-2023-6546 typically requires local access to the system, as it involves interactions between threads on a tty file descriptor.