Dangling pointer in Linux kernel BPF SRH handling
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 6 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
The Linux kernel from 4.18 before the fixed versions contains a flaw in BPF LWT_SEG6LOCAL programs. A program that invalidates its cached segment routing header and then calls bpf_skb_pull_data() can leave a per-CPU header pointer dangling, and later validation writes through it. A local user with low privileges can affect confidentiality, integrity and availability.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL An LWT_SEG6LOCAL program can invalidate its cached SRH with bpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(). The latter may reallocate skb->head, leaving the per-CPU SRH pointer dangling. Post-program SRH validation then writes through that pointer. Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL programs so the verifier rejects this unsafe helper combination. Other LWT program types continue to expose the helper through lwt_out_func_proto().
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Upgrade the Linux kernel to 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9 or 7.3. Red Hat lists Red Hat Enterprise Linux 6 as affected with no fix planned, and Red Hat Enterprise Linux 8, 9, 10 and OpenShift Container Platform 4 and 5 as affected without a fix and with no plan available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9, 7.3
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 |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-09 Threatist record created from CVE-2026-98383
- 2026-10-09 Alias added: GHSA-ph4x-4wh2-2qrm
- 2026-10-11 Affected versions changed · Red Hat
- 2026-10-11 CVSS score added · Red Hat
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Affected versions changed · Red Hat
- 2026-10-21 CVSS score changed · Red Hat
- 2026-10-24 CVSS score added · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/0f38472a2aa8704a6b514c0dfa9c32f3672b8f32
- https://git.kernel.org/stable/c/cae8674489f26edf7553fdd660599466cbb4c32f
- https://git.kernel.org/stable/c/9f9e57b5a3a033f95f49ef9d541340cdbcb80abb
- https://git.kernel.org/stable/c/df0072be6fc373cb22f9ea854d458b04e32a03cf
- https://git.kernel.org/stable/c/b9bb0e735460751b620156f800a4279a28573392
- https://git.kernel.org/stable/c/37b18688cd18fd86d2f35c212df1611862a26cd5
- https://git.kernel.org/stable/c/fca71ead7a20290af1e2046983eeafae43d21af1
- https://git.kernel.org/stable/c/e4a62833adff6ef0fe7c0b90393204fe3c26b5c5
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Sources
- CVE-2026-98383 · CVE Program
- CVE-2026-98383 · NVD
- FIRST EPSS
- GHSA-ph4x-4wh2-2qrm · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98383 · 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