net: Drop the lock in skb_may_tx_timestamp()
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-476.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 4.0 and later | 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.16, 6.19.6, 7.0 | Patch available | CNA |
- Linux VendorLinux Affected 4.0 and later Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.16, 6.19.6, 7.0 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.16, 6.19.6, 7.0
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-43216
- 2026-10-03 Alias added: GHSA-r977-p9g8-m7hx
- 2026-11-06 CISA SSVC decision points changed
References
Patch 3
Other 5
- 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
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2026-43216 · CVE Program
- CVE-2026-43216 · NVD
- FIRST EPSS
- GHSA-r977-p9g8-m7hx · GitHub Advisory Database · CC BY 4.0
- CVE-2026-43216 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences