GHSA-R977-P9G8-M7HX
Vulnerability from github – Published: 2026-05-06 12:30 – Updated: 2026-05-11 21:31In 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.
{
"affected": [],
"aliases": [
"CVE-2026-43216"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-06T12:16:41Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: Drop the lock in skb_may_tx_timestamp()\n\nskb_may_tx_timestamp() may acquire sock::sk_callback_lock. The lock must\nnot be taken in IRQ context, only softirq is okay. A few drivers receive\nthe timestamp via a dedicated interrupt and complete the TX timestamp\nfrom that handler. This will lead to a deadlock if the lock is already\nwrite-locked on the same CPU.\n\nTaking the lock can be avoided. The socket (pointed by the skb) will\nremain valid until the skb is released. The -\u003esk_socket and -\u003efile\nmember will be set to NULL once the user closes the socket which may\nhappen before the timestamp arrives.\nIf we happen to observe the pointer while the socket is closing but\nbefore the pointer is set to NULL then we may use it because both\npointer (and the file\u0027s cred member) are RCU freed.\n\nDrop the lock. Use READ_ONCE() to obtain the individual pointer. Add a\nmatching WRITE_ONCE() where the pointer are cleared.",
"id": "GHSA-r977-p9g8-m7hx",
"modified": "2026-05-11T21:31:31Z",
"published": "2026-05-06T12:30:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43216"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/983512f3a87fd8dc4c94dfa6b596b6e57df5aad7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e4c6efb3b70ff87f1df99efce2f8893717695718"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f3e4cceafad27c9363c33622732f86722846ec6f"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.