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TI-2026-81866 Aliases CVE-2026-99159GHSA-pqhv-wx6p-7gp4

Off-by-one sub-buffer index in Linux kernel persistent ring buffer

Priority LOW 22Published · Updated

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

Linux kernel versions from 6.12 are affected. The ring buffer function rb_meta_subbuf_idx() can return a sub-buffer index one too high on a persistent ring buffer, which leaves a NULL entry in the sub-buffer array. The kernel dereferences that entry when userspace maps trace_pipe_raw, and it writes the bad indices into the ring buffer metadata, so the next boot rejects the previous boot's trace.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

Description from the CNA

In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix the sub-buffer array base in rb_meta_subbuf_idx() On a persistent ring buffer, rb_meta_subbuf_idx() can return an index one sub-buffer too high. rb_setup_ids_meta_page() then fills subbuf_ids[] shifted by one and leaves subbuf_ids[0] NULL, which __rb_map_vma() dereferences when userspace maps trace_pipe_raw. rb_update_meta_reader() writes two such indices into meta->buffers[], which rb_cpu_meta_valid() would reject on the next boot, discarding the previous boot's trace. A CPU's sub-buffer array starts after its meta header and the nr_subbufs integers that follow, aligned up to a sub-buffer. rb_meta_subbuf_idx() inverts that calculation but skips only the integers, not the header, so its base is one sub-buffer low whenever the omitted header size crosses the alignment boundary. Invert the calculation with rb_subbufs_from_meta() rather than repeating it. rb_range_buffer() maps an index back to an address through the same helper, so the two directions can no longer disagree.

Why it matters now

EPSS 0.00176 7th percentileScored 2026-11-07
Fix Partial Linux (Linux): 6.12.115, 6.18.59, 7.2.13 +1Red Hat: 6 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux6.12 and later6.12.115, 6.18.59, 7.2.13, 7.3Patch availableCNA
  • Linux VendorLinux Affected 6.12 and later Fixed in 6.12.115, 6.18.59, 7.2.13, 7.3 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

Update to Linux kernel 6.12.115, 6.18.59, 7.2.13 or 7.3. For Red Hat Enterprise Linux 7, 8, 9 and 10 and Red Hat OpenShift Container Platform 4 and 5, the sources list no fixed version.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

  • Fix · CNA Linux (Linux) Fixed in 6.12.115, 6.18.59, 7.2.13, 7.3

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 5AffectedNo fix yet: Fix deferred
Not affected: 1 product
  • Red Hat Enterprise Linux 6

Timeline

  1. 2026-10-28 Threatist record created from CVE-2026-99159
  2. 2026-10-28 Alias added: GHSA-pqhv-wx6p-7gp4
  3. 2026-10-30 Fix available: Linux/Linux@0c0cf2240bb5ca5704ea932ba66ee54f43173915, Linux/[email protected] · CNA
  4. 2026-10-30 1 new reference · CNA
  5. 2026-11-01 Affected versions changed · Red Hat
  6. 2026-11-01 CVSS score added · Red Hat
  7. 2026-11-02 Affected versions changed · Red Hat

References

Other 4

  • 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-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
See all 21741 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences