Unbounded recursion in Linux kernel bridge multicast cleanup
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: 6 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel bridge, in versions from 5.10, removes multicast port groups recursively in br_multicast_sg_del_exclude_ports. Each automatically added exclude port adds one kernel stack frame, so a large number of ports can hit the stack guard page.
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: bridge: avoid recursive multicast port cleanup br_multicast_sg_del_exclude_ports() removes automatically added STAR_EXCL port groups by calling br_multicast_del_pg(). For S,G entries, that deletion calls back into br_multicast_sg_del_exclude_ports(), so a large number of STAR_EXCL ports consumes one kernel stack frame per port and can hit the stack guard page. Keep the complete port-group deletion path for cleanup, but suppress the S,G exclude-port cleanup while that helper is already walking the same entry. Normal deletion callers retain the existing behavior.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.10 and later | 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 5.10 and later Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11, 7.3 Patch available CNA
Remediation
Upgrade the Linux kernel to 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11 or 7.3. Red Hat lists no fix available for Red Hat Enterprise Linux 8, 9 and 10 and OpenShift Container Platform 4 and 5, and no fix planned for Red Hat Enterprise Linux 6.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.57, 7.2.11, 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
- 2026-10-23 Threatist record created from CVE-2026-99031
- 2026-10-23 Alias added: GHSA-c83g-q254-qmxr
- 2026-10-29 Affected versions changed · Red Hat
- 2026-10-29 CVSS score added · Red Hat
- 2026-10-30 Fix available: Linux/Linux@0ed8edcbcf2290dba13c1beeba27fc19ad38515b, Linux/Linux@26142868b0767e95e28b7a1237f58b292b54d1d9, Linux/[email protected] +3 · CNA
- 2026-10-30 3 new references · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/0ed8edcbcf2290dba13c1beeba27fc19ad38515b
- https://git.kernel.org/stable/c/6a7385f6605958aa69eeb185c91f45d77640d1e2
- https://git.kernel.org/stable/c/26142868b0767e95e28b7a1237f58b292b54d1d9
- https://git.kernel.org/stable/c/695a5a4c69c922d9296b2d7ad5f1ce8c6858fc64
- https://git.kernel.org/stable/c/2fb87c6025f90191516bee3ce14b42eb3e1cfed7
- https://git.kernel.org/stable/c/d109141ba14652146089ef78b32d5e4d5285ebad
- https://git.kernel.org/stable/c/7931fb9181421953f3133b408b0f2e2b8dd68b61
- https://git.kernel.org/stable/c/5158353121bae4f552cb677ce8c5c3ef52f93a0d
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Sources
- CVE-2026-99031 · CVE Program
- CVE-2026-99031 · NVD
- FIRST EPSS
- GHSA-c83g-q254-qmxr · GitHub Advisory Database · CC BY 4.0
- CVE-2026-99031 · 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