Linux Kernel up to 7.3-rc3 KVM PPC Book3S HV kvmhv_emulate_tlbie_all_lpid use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k0.56-

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.3-rc3 and classified as very critical. This affects the function kvmhv_emulate_tlbie_all_lpid of the component KVM PPC Book3S HV. Such manipulation leads to use after free. This vulnerability is uniquely identified as CVE-2026-98283. The attack can be launched remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.3-rc3. It has been rated as very critical. Affected by this issue is the function kvmhv_emulate_tlbie_all_lpid of the component KVM PPC Book3S HV. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-98283 since 09/25/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 10/06/2026).

Upgrading to version 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8 or 7.3-rc4 eliminates this vulnerability. Applying the patch 4d8f7b1f586375df8bce23a0909566ad5e852259/e37fba1ba69385cff2d0e60b371ee19e7d1852d1/24b634852413229bb8340d908b115c3365f3a247/fbf69b7d0555ee83c871f58750770f74b7179ad1/ec2d7a52b3996ae81131617b4afc0af31583c1b4/51938dfa8a51a4f85328413fca9b6e21f9d2d088 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.189/6.6.158/6.12.112/6.18.54/7.2.8/7.3-rc4
Patch: 4d8f7b1f586375df8bce23a0909566ad5e852259/e37fba1ba69385cff2d0e60b371ee19e7d1852d1/24b634852413229bb8340d908b115c3365f3a247/fbf69b7d0555ee83c871f58750770f74b7179ad1/ec2d7a52b3996ae81131617b4afc0af31583c1b4/51938dfa8a51a4f85328413fca9b6e21f9d2d088

Timelineinfo

09/25/2026 CVE reserved
10/06/2026 +11 days Advisory disclosed
10/06/2026 +0 days VulDB entry created
10/06/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98283 (🔒)
GCVE (CVE): GCVE-0-2026-98283
GCVE (VulDB): GCVE-100-414152

Entryinfo

Created: 10/06/2026 13:12
Changes: 10/06/2026 13:12 (59)
Complete: 🔍
Cache ID: 216::103

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