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TI-2026-68174 Aliases CVE-2026-98283GHSA-f6vc-5ch2-5vxm

Use-after-free in Linux kernel KVM nested guest TLB invalidation

Priority LOW 37Published · Updated

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: 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

Linux kernel versions from 4.20 are affected in the KVM PowerPC Book3S HV code. The kvmhv_emulate_tlbie_all_lpid() function drops the MMU lock while it still uses a nested guest pointer that it holds no reference to, so a concurrent request can free that structure first. This causes a use-after-free. A local user with low privileges can trigger it, and the impact on confidentiality, integrity and availability is high.

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: KVM: PPC: Book3S HV: fix use-after-free in kvmhv_emulate_tlbie_all_lpid() kvmhv_emulate_tlbie_all_lpid() iterates the nested-guest IDR and drops mmu_lock before calling kvmhv_emulate_tlbie_lpid(), but does not hold a reference on the kvm_nested_guest pointer obtained from the IDR. A concurrent vCPU issuing a single-LPID tlbie (is=2, ric=2) can race through kvmhv_flush_nested() -> kvmhv_remove_nested() -> idr_remove / --refcnt -> kvmhv_release_nested() -> kfree(gp) in that window, leaving the iterating vCPU with a dangling pointer. The subsequent mutex_lock(&gp->tlb_lock) and accesses to gp->shadow_pgtable, gp->shadow_lpid and gp->l1_host all touch freed memory. The free path is fully L1-controlled. Fix this by incrementing gp->refcnt inside the loop before dropping mmu_lock, mirroring what kvmhv_get_nested() does, and releasing the reference with kvmhv_put_nested() after the per-guest work completes. This is the same get/put discipline already used at every other call site that drops mmu_lock while holding a nested-guest pointer.

Why it matters now

EPSS 0.00126 2nd percentileScored 2026-11-07
Fix Partial Linux (Linux): 6.1.189, 6.6.158, 6.12.112 +3Red Hat: 3 without a fix

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux4.20 and later6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8, 7.3Patch availableCNA
  • Linux VendorLinux Affected 4.20 and later Fixed in 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8, 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

Upgrade to Linux kernel 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8 or 7.3, matching the branch in use. Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8 and Red Hat OpenShift Container Platform 4 are affected, and Red Hat lists no fix plan for them.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA Linux (Linux) Fixed in 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8, 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
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat OpenShift Container Platform 4AffectedNo fix yet
Not affected: 5 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 9
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Container Platform 5

Timeline

  1. 2026-10-06 Threatist record created from CVE-2026-98283
  2. 2026-10-06 Alias added: GHSA-f6vc-5ch2-5vxm
  3. 2026-10-07 CVSS score added · CNA
  4. 2026-10-11 Affected versions changed · Red Hat
  5. 2026-10-11 CVSS score added · Red Hat
  6. 2026-10-19 Fix available: Linux/[email protected] · CNA
  7. 2026-10-30 Affected versions changed · Red Hat

References

Other 6

  • 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