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CVE-2026-89984

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : <=6.1.*, <=6.12.*, 5.15.221, 47125db27e47e9d44c878bf8925aa057824bb0d5, 5.10.270, 0, 6.1.188, 6.18.51, <ca19a175e89b7de604fab736436cbab74030b47a, <e2b0575900ff72aa82748af96e7bd564ade5157a, <3c492c8eba02698ca893a9a13388d2adf6dfb839, <=5.10.*, <=6.6.*, 7.2.5, 6.6.157, <68c4b780b266a435261a1e029bede5ee3c2735cc, <b589147f54adc62e4172e4acf079ad5fb7b3687f, <=6.18.*, 5.9, <be0628a101ac05b085aaa4f650d48bd3915e80fa, <5.9, 6.12.110, <=7.2.*, <=*, <=5.15.*, <f3705db4e6378cc1b91a38ce0fe2f879055e23ca, <6ac26161db27f7fb9d9e89ae240dbe52795496cc, 7.3

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.

Gravité et risque d'exploitation

CVE-2026-89984 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.21 %, ce qui la place devant 10.6 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=6.12.*, 5.15.221, 47125db27e47e9d44c878bf8925aa057824bb0d5, 5.10.270, 0, 6.1.188, 6.18.51, <ca19a175e89b7de604fab736436cbab74030b47a, <e2b0575900ff72aa82748af96e7bd564ade5157a, <3c492c8eba02698ca893a9a13388d2adf6dfb839, <=5.10.*, <=6.6.*, 7.2.5, 6.6.157, <68c4b780b266a435261a1e029bede5ee3c2735cc, <b589147f54adc62e4172e4acf079ad5fb7b3687f, <=6.18.*, 5.9, <be0628a101ac05b085aaa4f650d48bd3915e80fa, <5.9, 6.12.110, <=7.2.*, <=*, <=5.15.*, <f3705db4e6378cc1b91a38ce0fe2f879055e23ca, <6ac26161db27f7fb9d9e89ae240dbe52795496cc, 7.3) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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