Unbounded recursion in Linux kernel IP-in-IP GSO segmentation
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
The Linux kernel from 3.13 is affected. IP-in-IP GSO segmentation re-enters the IPv4 and IPv6 GSO handlers for each nested IP header without a limit. A deep chain of nested IP headers can exhaust the kernel stack.
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: net: gso: limit recursive IP-in-IP segmentation IP-in-IP GSO can re-enter inet_gso_segment() or ipv6_gso_segment() for each nested IP header. encap_level tracks header bytes, not callback depth, so a deep chain can exhaust the kernel stack. Making inet_gso_segment() stackable introduced unbounded IPv4 nesting; IPIP GSO/TSO later made the path reachable. The IPv6 stackable path was introduced separately and uses the same guard. Count IPv4 and IPv6 GSO handler entries in skb_gso_cb, initialized once per top-level GSO operation and preserved across GRE/UDP context changes. Use the existing IP_TUNNEL_RECURSION_LIMIT for both handlers. The first five entries pass, and the sixth returns -EINVAL before dispatching another GSO callback.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Update the Linux kernel to 6.18.60, 7.2.10 or 7.3. Red Hat reports no available plan for Red Hat Enterprise Linux 6, 7, 8, 9 and 10 or Red Hat OpenShift Container Platform 4 and 5.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 6.18.60, 7.2.10, 7.3
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix yet |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98853
- 2026-10-18 Alias added: GHSA-3hxr-fh6w-v89j
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-24 Affected versions changed · Red Hat
- 2026-10-24 CVSS score added · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
- 2026-10-30 Fix available: Linux/Linux@388604279da3d0698a151efa4fb6d852efa0de4a, Linux/[email protected] · CNA
- 2026-10-30 1 new reference · CNA
References
More Linux vulnerabilities
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- TI-2021-02452 Incorrect authorization in Ubuntu linux kernel 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
Sources
- CVE-2026-98853 · CVE Program
- CVE-2026-98853 · NVD
- FIRST EPSS
- GHSA-3hxr-fh6w-v89j · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98853 · 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