CVE-2026-43216 Details
Description
In the Linux kernel, the following vulnerability has been resolved: net: Drop the lock in skb_may_tx_timestamp() skb_may_tx_timestamp() may acquire sock::sk_callback_lock. The lock must not be taken in IRQ context, only softirq is okay. A few drivers receive the timestamp via a dedicated interrupt and complete the TX timestamp from that handler. This will lead to a deadlock if the lock is already write-locked on the same CPU. Taking the lock can be avoided. The socket (pointed by the skb) will remain valid until the skb is released. The ->sk_socket and ->file member will be set to NULL once the user closes the socket which may happen before the timestamp arrives. If we happen to observe the pointer while the socket is closing but before the pointer is set to NULL then we may use it because both pointer (and the file's cred member) are RCU freed. Drop the lock. Use READ_ONCE() to obtain the individual pointer. Add a matching WRITE_ONCE() where the pointer are cleared.
A vulnerability exists in the Linux kernel's handling of socket locks during timestamp processing, specifically within the 'skb_may_tx_timestamp()' function. This function may acquire the 'sk_callback_lock', which should not be held in interrupt context, as it can lead to a deadlock. Some drivers use a dedicated interrupt to manage transmission timestamps, and if the lock is already write-locked on the same CPU, a deadlock can occur. The vulnerability arises because the socket, referenced by the skb, remains valid until the skb is released. However, the 'sk_socket' and 'file' members can be set to NULL when the socket is closed, potentially before the timestamp is processed. If the pointer is accessed during this window, it can lead to improper handling of the timestamp. The issue has been addressed by modifying the lock management and using atomic operations to safely read and clear the socket pointers.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been fixed. Instructions for downloading the patched version are available on the Linux kernel official website.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-476 | NULL Pointer Dereference | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 4.0, < 6.18.16 >= 6.19, < 6.19.6 7.0 rc1 |
CPE
Remediation
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Change History
7 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 8, 2026 | CVE Modified | siemens-SADP |
| Sep 8, 2026 | CVE Modified | kernel.org |
| Jul 24, 2026 | CVE Modified | kernel.org |
| Jul 4, 2026 | CVE Modified | kernel.org |
| Jun 17, 2026 | CVE Modified | kernel.org |
| May 11, 2026 | Initial Analysis | [email protected] |
| May 6, 2026 | New CVE Received | kernel.org |