CVE Catalog

CVE-2026-98283

HighCVSS 8.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.14%

3th percentile - higher than 3% of all known CVEs

Summary

In the Linux kernel, KVM for PowerPC (Book3S HV) has a use-after-free vulnerability in kvmhv_emulate_tlbie_all_lpid(). The function iterates nested-guest IDs without holding a reference, allowing a race with a concurrent vCPU that can free the memory. The fix increments the reference count before dropping the lock and releases it after the work.

Risk Assessment

The vulnerability may lead to memory corruption, potentially causing system crashes or privilege escalation in virtualized environments.

Recommendation

Apply the Linux kernel update containing the fix for CVE-2026-98283. Ensure KVM/PowerPC environments are updated.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS