Bug 2383522 (CVE-2025-38462)

Summary: CVE-2025-38462 kernel: Linux kernel: Denial of Service in vsock due to TOCTOU race condition
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel. A local user could exploit a Time-of-check to time-of-use (TOCTOU) race condition in the vsock implementation. This occurs when functions like `vsock_find_cid()` and `vsock_dev_do_ioctl()` race with module unload, causing a pointer to become NULL after it has been checked. Successful exploitation of this vulnerability leads to a null-pointer dereference, resulting in a system crash and a Denial of Service (DoS).
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Description OSIDB Bzimport 2025-07-25 16:04:04 UTC
In the Linux kernel, the following vulnerability has been resolved:

vsock: Fix transport_{g2h,h2g} TOCTOU

vsock_find_cid() and vsock_dev_do_ioctl() may race with module unload.
transport_{g2h,h2g} may become NULL after the NULL check.

Introduce vsock_transport_local_cid() to protect from a potential
null-ptr-deref.

KASAN: null-ptr-deref in range [0x0000000000000118-0x000000000000011f]
RIP: 0010:vsock_find_cid+0x47/0x90
Call Trace:
 __vsock_bind+0x4b2/0x720
 vsock_bind+0x90/0xe0
 __sys_bind+0x14d/0x1e0
 __x64_sys_bind+0x6e/0xc0
 do_syscall_64+0x92/0x1c0
 entry_SYSCALL_64_after_hwframe+0x4b/0x53

KASAN: null-ptr-deref in range [0x0000000000000118-0x000000000000011f]
RIP: 0010:vsock_dev_do_ioctl.isra.0+0x58/0xf0
Call Trace:
 __x64_sys_ioctl+0x12d/0x190
 do_syscall_64+0x92/0x1c0
 entry_SYSCALL_64_after_hwframe+0x4b/0x53