Medium 5.5Published May 6, 2026

CVE-2026-43216net: Drop the lock in skb_may_tx_timestamp()

Updated under an hour ago (Oct 28, 2026, 9:10 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from b245be1f4db1a0394e4b6eb66059814b46670ac3 before 4839cbda8f13e99ce2bb3b593f5cc3288415684b; from b245be1f4db1a0394e4b6eb66059814b46670ac3 before 3709d73ace37e9aaebb688f5a5cf706d74350b64; from b245be1f4db1a0394e4b6eb66059814b46670ac3 before cf7599116c4c0082fd25cb1bf0254631da0ed06e; from b245be1f4db1a0394e4b6eb66059814b46670ac3 before cd2463ec60f0d6e460078037c86f9d0947ee1ff6; from b245be1f4db1a0394e4b6eb66059814b46670ac3 before c770217044d9cbe16a1f7c385cf080ed06a2fc04; from b245be1f4db1a0394e4b6eb66059814b46670ac3 before f3e4cceafad27c9363c33622732f86722846ec6f; from b245be1f4db1a0394e4b6eb66059814b46670ac3 before e4c6efb3b70ff87f1df99efce2f8893717695718; from b245be1f4db1a0394e4b6eb66059814b46670ac3 before 983512f3a87fd8dc4c94dfa6b596b6e57df5aad7	CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
linux linux_kernel linux:linux_kernel	from 4.0 before 6.18.16; from 6.19 before 6.19.6; 7.0	NVD

References

References

https://git.kernel.org/stable/c/4839cbda8f13e99ce2bb3b593f5cc3288415684b
https://git.kernel.org/stable/c/3709d73ace37e9aaebb688f5a5cf706d74350b64
https://git.kernel.org/stable/c/cf7599116c4c0082fd25cb1bf0254631da0ed06e
https://git.kernel.org/stable/c/cd2463ec60f0d6e460078037c86f9d0947ee1ff6
https://git.kernel.org/stable/c/c770217044d9cbe16a1f7c385cf080ed06a2fc04
https://git.kernel.org/stable/c/f3e4cceafad27c9363c33622732f86722846ec6f	patch
https://git.kernel.org/stable/c/e4c6efb3b70ff87f1df99efce2f8893717695718	patch
https://git.kernel.org/stable/c/983512f3a87fd8dc4c94dfa6b596b6e57df5aad7	patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-457936.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.