Linux kernel netlink socket filters read data before messages
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 7 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
Versions of the Linux kernel from 2.6.26 are affected. The netlink subsystem does not reset the skb network and MAC header offsets before unicast and broadcast delivery, so socket filters can read data from before the message. An unprivileged user who can attach a classic socket filter to a NETLINK_RDMA socket can read this data through the length of a delivered IWPM reply.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: netlink: reset skb headers before unicast and multicast filtering Socket filters can use SKF_NET_OFF and SKF_LL_OFF to read relative to an skb's network and MAC headers. Netlink producers may reserve headroom without resetting those headers, allowing a receiving socket's filter to read data before the initialized message. For example, IWPM HELLO replies are allocated with dev_alloc_skb(), which reserves NET_SKB_PAD bytes. An unprivileged NETLINK_RDMA user can attach a classic socket filter and disclose this headroom through the length of the delivered reply. The resets in netlink_dump() do not help because IWPM sends a separately allocated skb through netlink_unicast(). Reset both headers before running the receiver's filter in unicast and broadcast delivery, as is already done for dump skbs. This also covers other netlink producers that reserve headroom without changing their allocation or message-building code.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Update to Linux kernel 5.10.273, 5.15.224, 6.6.161, 6.12.115, 6.18.59, 7.2.13 or 7.3, which contain the fix. Red Hat Enterprise Linux 6 has no fix planned. Red Hat Enterprise Linux 7, 8, 9 and 10 and Red Hat OpenShift Container Platform 4 and 5 have no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
- Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.6.161, 6.12.115, 6.18.59, 7.2.13, 7.3
Vendor assessments
Red Hat
Red Hat rating: Low. 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 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-28 Threatist record created from CVE-2026-99211
- 2026-10-28 Alias added: GHSA-rx9x-87v5-hrch
- 2026-10-29 Affected versions changed · Red Hat
- 2026-10-29 CVSS score added · Red Hat
- 2026-10-30 Fix available: Linux/Linux@4123f8d2099863e2421187af9d87b45e8eebd867, Linux/[email protected], Linux/[email protected] +5 · CNA
- 2026-10-30 4 new references · CNA
- 2026-11-07 Affected versions changed · Red Hat
References
Other 7
- https://git.kernel.org/stable/c/4123f8d2099863e2421187af9d87b45e8eebd867
- https://git.kernel.org/stable/c/6ec7cc02458c6a1509377a7f2eec9c7b1a355b5e
- https://git.kernel.org/stable/c/ea0e0fc4c72f71bd6d8bf460bfe309b61c35b548
- https://git.kernel.org/stable/c/c69db9e1f5cf886d4e3011313761a0f63a1d0da0
- https://git.kernel.org/stable/c/06791594274f87c29f1a9f1961d700272716a49d
- https://git.kernel.org/stable/c/06935da5de83aa8b98841563894857e7d2f80e47
- https://git.kernel.org/stable/c/8bf659bd54e1f00e34cf5244b1d289c506fa47c0
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- 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
Sources
- CVE-2026-99211 · CVE Program
- CVE-2026-99211 · NVD
- FIRST EPSS
- GHSA-rx9x-87v5-hrch · GitHub Advisory Database · CC BY 4.0
- CVE-2026-99211 · 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