tty: n_gsm: Fix use-after-free in gsm_cleanup_mux
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 5 fixed, 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.
Summary
In the Linux kernel, the following vulnerability has been resolved: tty: n_gsm: Fix use-after-free in gsm_cleanup_mux BUG: KASAN: slab-use-after-free in gsm_cleanup_mux+0x77b/0x7b0 drivers/tty/n_gsm.c:3160 [n_gsm] Read of size 8 at addr ffff88815fe99c00 by task poc/3379 CPU: 0 UID: 0 PID: 3379 Comm: poc Not tainted 6.11.0+ #56 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 Call Trace: <TASK> gsm_cleanup_mux+0x77b/0x7b0 drivers/tty/n_gsm.c:3160 [n_gsm] __pfx_gsm_cleanup_mux+0x10/0x10 drivers/tty/n_gsm.c:3124 [n_gsm] __pfx_sched_clock_cpu+0x10/0x10 kernel/sched/clock.c:389 update_load_avg+0x1c1/0x27b0 kernel/sched/fair.c:4500 __pfx_min_vruntime_cb_rotate+0x10/0x10 kernel/sched/fair.c:846 __rb_insert_augmented+0x492/0xbf0 lib/rbtree.c:161 gsmld_ioctl+0x395/0x1450 drivers/tty/n_gsm.c:3408 [n_gsm] _raw_spin_lock_irqsave+0x92/0xf0 arch/x86/include/asm/atomic.h:107 __pfx_gsmld_ioctl+0x10/0x10 drivers/tty/n_gsm.c:3822 [n_gsm] ktime_get+0x5e/0x140 kernel/time/timekeeping.c:195 ldsem_down_read+0x94/0x4e0 arch/x86/include/asm/atomic64_64.h:79 __pfx_ldsem_down_read+0x10/0x10 drivers/tty/tty_ldsem.c:338 __pfx_do_vfs_ioctl+0x10/0x10 fs/ioctl.c:805 tty_ioctl+0x643/0x1100 drivers/tty/tty_io.c:2818 Allocated by task 65: gsm_data_alloc.constprop.0+0x27/0x190 drivers/tty/n_gsm.c:926 [n_gsm] gsm_send+0x2c/0x580 drivers/tty/n_gsm.c:819 [n_gsm] gsm1_receive+0x547/0xad0 drivers/tty/n_gsm.c:3038 [n_gsm] gsmld_receive_buf+0x176/0x280 drivers/tty/n_gsm.c:3609 [n_gsm] tty_ldisc_receive_buf+0x101/0x1e0 drivers/tty/tty_buffer.c:391 tty_port_default_receive_buf+0x61/0xa0 drivers/tty/tty_port.c:39 flush_to_ldisc+0x1b0/0x750 drivers/tty/tty_buffer.c:445 process_scheduled_works+0x2b0/0x10d0 kernel/workqueue.c:3229 worker_thread+0x3dc/0x950 kernel/workqueue.c:3391 kthread+0x2a3/0x370 kernel/kthread.c:389 ret_from_fork+0x2d/0x70 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:257 Freed by task 3367: kfree+0x126/0x420 mm/slub.c:4580 gsm_cleanup_mux+0x36c/0x7b0 drivers/tty/n_gsm.c:3160 [n_gsm] gsmld_ioctl+0x395/0x1450 drivers/tty/n_gsm.c:3408 [n_gsm] tty_ioctl+0x643/0x1100 drivers/tty/tty_io.c:2818 [Analysis] gsm_msg on the tx_ctrl_list or tx_data_list of gsm_mux can be freed by multi threads through ioctl,which leads to the occurrence of uaf. Protect it by gsm tx lock.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.15.209 to before 5.16; 5.18.18 to before 5.19; 5.19.2 to before 5.20 | 5.16, 5.19, 5.20 | Patch available | CNA |
| Linux | Linux | 6.0 and later | 6.1.114, 6.6.58, 6.11.5, 6.12 | Patch available | CNA |
- Linux VendorLinux Affected 5.15.209 to before 5.16; 5.18.18 to before 5.19; 5.19.2 to before 5.20 Fixed in 5.16, 5.19, 5.20 Patch available CNA
- Linux VendorLinux Affected 6.0 and later Fixed in 6.1.114, 6.6.58, 6.11.5, 6.12 Patch available CNA
CPE configurations NVD · 4
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | before 6.1.114; 6.2 to before 6.6.58; 6.7 to before 6.11.5 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:* | 6.12 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:* | 6.12 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:* | 6.12 rc3 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions before 6.1.114; 6.2 to before 6.6.58; 6.7 to before 6.11.5 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:* Versions 6.12 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:* Versions 6.12 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:* Versions 6.12 rc3 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.16, 5.19, 5.20
- Fix · CNA Linux (Linux) Fixed in 6.1.114, 6.6.58, 6.11.5, 6.12
Red Hat 1 advisory
- RHSA-2025:6966 Released 2025-05-13 · Red Hat rating Moderatekernel security update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-570.12.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.12.1.el9_6, kernel-64k-devel-5.14.0-570.12.1.el9_6 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-570.12.1.el9_6, kernel-64k-5.14.0-570.12.1.el9_6, kernel-64k-core-5.14.0-570.12.1.el9_6 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-570.12.1.el9_6, libperf-5.14.0-570.12.1.el9_6
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-570.12.1.el9_6, kernel-rt-64k-5.14.0-570.12.1.el9_6, kernel-rt-64k-core-5.14.0-570.12.1.el9_6 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-570.12.1.el9_6, kernel-rt-core-5.14.0-570.12.1.el9_6, kernel-rt-debug-5.14.0-570.12.1.el9_6 +11
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2025:6966 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2025:6966 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2025:6966 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2025:6966 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2025:6966 |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-02 Threatist record created from CVE-2024-50073
- 2026-10-03 Alias added: GHSA-76p7-w946-wvch
- 2026-10-29 Affected versions changed · Red Hat
References
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2024-50073 · CVE Program
- CVE-2024-50073 · NVD
- FIRST EPSS
- GHSA-76p7-w946-wvch · GitHub Advisory Database · CC BY 4.0
- CVE-2024-50073 · Red Hat security data · CC BY 4.0
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