CVE-2025-21670: Null Pointer Dereference
First published: Fri Jan 31 2025(Updated: )
In the Linux kernel, the following vulnerability has been resolved: vsock/bpf: return early if transport is not assigned Some of the core functions can only be called if the transport has been assigned. As Michal reported, a socket might have the transport at NULL, for example after a failed connect(), causing the following trace: BUG: kernel NULL pointer dereference, address: 00000000000000a0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 12faf8067 P4D 12faf8067 PUD 113670067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 15 UID: 0 PID: 1198 Comm: a.out Not tainted 6.13.0-rc2+ RIP: 0010:vsock_connectible_has_data+0x1f/0x40 Call Trace: vsock_bpf_recvmsg+0xca/0x5e0 sock_recvmsg+0xb9/0xc0 __sys_recvfrom+0xb3/0x130 __x64_sys_recvfrom+0x20/0x30 do_syscall_64+0x93/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e So we need to check the `vsk->transport` in vsock_bpf_recvmsg(), especially for connected sockets (stream/seqpacket) as we already do in __vsock_connectible_recvmsg().
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | >=6.13.0-rc2 | |
| Linux Kernel | >=6.4<6.6.74 | |
| Linux Kernel | >=6.7<6.12.11 | |
| Linux Kernel | =6.13-rc1 | |
| Linux Kernel | =6.13-rc2 | |
| Linux Kernel | =6.13-rc3 | |
| Linux Kernel | =6.13-rc4 | |
| Linux Kernel | =6.13-rc5 | |
| Linux Kernel | =6.13-rc6 | |
| Linux Kernel | =6.13-rc7 |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2025-21670?
CVE-2025-21670 has a moderate severity rating due to its impact on socket operations in the Linux kernel.
How do I fix CVE-2025-21670?
To fix CVE-2025-21670, update your Linux kernel to the latest version that includes the patch for this vulnerability.
What versions of the Linux kernel are affected by CVE-2025-21670?
CVE-2025-21670 affects Linux kernel versions ranging from 6.4 to 6.12.11, as well as the 6.13 pre-release versions.
What components are impacted by CVE-2025-21670?
CVE-2025-21670 impacts the vsock transport layer within the Linux kernel, affecting its socket functionalities.
Is CVE-2025-21670 a remote vulnerability?
CVE-2025-21670 is not specifically a remote vulnerability, as it pertains to internal kernel behavior related to socket transport handling.
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