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CVE-2026-89984— perf/x86/intel: Fix kernel address leakages in LBR stack

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

以下是该漏洞描述的中文翻译： 在 Linux 内核中，以下漏洞已得到修复： perf/x86/intel：修复 LBR 堆栈中的内核地址泄露问题 在架构级 LBR（Last Branch Record，最后分支记录）获得 CPL（特权级别）过滤支持之前，仅用户空间的分支堆栈中仍可能包含内核地址。因此，即使请求了 （仅用户空间分支采样），内核分支记录仍可能暴露给用户空间。 例如，在 Intel Tiger Lake 平台上，以下命令仍可能报告源自内核空间地址的 SYSRET/ERET 条目： 输出示例： 问题的根源在

AI Predicted 5.5 Difficulty: Moderate EPSS 0.21% · P10

Possible ATT&CK Techniques 1 AI

T1059 · Command and Scripting Interpreter

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 47125db27e47e9d44c878bf8925aa057824bb0d5< f3705db4e6378cc1b91a38ce0fe2f879055e23ca affected
47125db27e47e9d44c878bf8925aa057824bb0d5< b589147f54adc62e4172e4acf079ad5fb7b3687f affected
47125db27e47e9d44c878bf8925aa057824bb0d5< be0628a101ac05b085aaa4f650d48bd3915e80fa affected
47125db27e47e9d44c878bf8925aa057824bb0d5< ca19a175e89b7de604fab736436cbab74030b47a affected
47125db27e47e9d44c878bf8925aa057824bb0d5< 6ac26161db27f7fb9d9e89ae240dbe52795496cc affected
47125db27e47e9d44c878bf8925aa057824bb0d5< 3c492c8eba02698ca893a9a13388d2adf6dfb839 affected
47125db27e47e9d44c878bf8925aa057824bb0d5< 68c4b780b266a435261a1e029bede5ee3c2735cc affected
47125db27e47e9d44c878bf8925aa057824bb0d5< e2b0575900ff72aa82748af96e7bd564ade5157a affected
… +10 more rows
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I. Basic Information for CVE-2026-89984

Vulnerability Information
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Vulnerability Title
perf/x86/intel: Fix kernel address leakages in LBR stack
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: perf/x86/intel: Fix kernel address leakages in LBR stack Before Arch LBR gained CPL filtering support, a user-only branch stack could still contain kernel addresses. As a result, kernel branch records may be exposed to user space even when PERF_SAMPLE_BRANCH_USER is requested. For example, on Intel Tiger Lake, the following command can still report SYSRET/ERET entries with kernel-space from addresses: $ ./perf record -e cycles:p -o - --branch-filter any,save_type,u -- \ ./perf bench syscall basic --loop 1000 | \ ./perf script -i - --fields brstack|tr ' ' '\n'| \ grep -E '0x[89a-f][0-9a-f]{15}' Total time: 0.000 [sec] 0.219000 usecs/op 4,566,210 ops/sec [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.551 MB - ] 0xffffffff93c001c8/0x7f12a2b1d647/P/-/-/16959/SYSRET/- 0xffffffff93c001c8/0x7f12a2b1d5c2/P/-/-/17535/SYSRET/- 0xffffffff93c01928/0x7f12a2861000/P/-/-/6719/ERET/- 0xffffffff93c01928/0x7f12a297a000/P/-/-/8575/ERET/- The problem is that intel_pmu_lbr_filter() does not fully validate the privilege level of sampled entries. It filters some mismatches based on the branch type and the to address, but it does not reject entries whose from address violates the requested branch privilege filter. Fix this by extending software filtering to validate both from and to addresses against br_sel. Any LBR entry contains kernel address does not match the requested user filter is dropped. This prevents kernel addresses from appearing in user-only branch stacks.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 47125db27e47e9d44c878bf8925aa057824bb0d5 ~ f3705db4e6378cc1b91a38ce0fe2f879055e23ca -
Linux Linux 5.9 -

II. Public POCs for CVE-2026-89984

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III. Intelligence Information for CVE-2026-89984

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Other References for CVE-2026-89984 (8)

Same Patch Batch · Linux · 2026-09-16 · 276 CVEs total

CVE-2026-90048 9.8 CRITICAL fs/ntfs3: fix slab-out-of-bounds write in ni_create_attr_list()
CVE-2026-90012 9.8 CRITICAL spi: Fix DMA mapping ownership on partial map failure
CVE-2026-89970 9.8 CRITICAL nvmet-auth: Synchronize timeout work during SQ teardown
CVE-2026-89857 9.8 CRITICAL scsi: qla2xxx: Hold qpair lock when sending NVMe LS reject
CVE-2026-89969 9.8 CRITICAL nvmet-tcp: fix out-of-bounds write when receiving an over-long PDU
CVE-2026-89847 9.8 CRITICAL scsi: qla2xxx: Avoid double completion in async IOCB timeout
CVE-2026-89972 9.8 CRITICAL nvme: add missing SRCU grace period in error path
CVE-2026-89990 9.8 CRITICAL ceph: lock mutex in ceph_mds_check_access()
CVE-2026-90036 9.8 CRITICAL NFSD: Prevent client use-after-free during blocked-lock reaping
CVE-2026-90038 9.8 CRITICAL NFSD: Prevent client use-after-free during export state revocation
CVE-2026-90037 9.8 CRITICAL NFSD: Prevent client use-after-free during close_lru reaping
CVE-2026-89788 9.8 CRITICAL ksmbd: fix tree connection use-after-free in smb2_tree_connect()
CVE-2026-89783 9.8 CRITICAL xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full
CVE-2026-90042 9.8 CRITICAL ceph: properly decrypt filenames in vmalloc() buffers
CVE-2026-89778 9.8 CRITICAL isofs: fix out-of-bounds page array access on empty zisofs block
CVE-2026-89915 9.3 CRITICAL KVM: arm64: Remove VM-wide VNCR mapping counter
CVE-2026-90049 9.3 CRITICAL net: skbuff: don't skb_tx_error() the source skb in skb_zerocopy()
CVE-2026-89775 9.3 CRITICAL KVM: arm64: Handle negative S1 walk levels in VNCR TLB size evaluation
CVE-2026-89916 9.3 CRITICAL KVM: arm64: Make VNCR invalidation participate in MMU invalidation retry
CVE-2026-89930 9.3 CRITICAL KVM: nVMX: Service local TLB flushes on failed nested VM-Enter

Showing top 20 of 276 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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