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TI-2026-45440 Aliases CVE-2026-63875GHSA-h9hg-3wv2-x6j7

arm64: tlb: Flush walk cache when unsharing PMD tables

Priority LOW 35CWE-459Published · 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: 13 fixed, 1 without a fix

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

Summary

In the Linux kernel, the following vulnerability has been resolved: arm64: tlb: Flush walk cache when unsharing PMD tables When huge_pmd_unshare() is called to unshare a PMD table, the tlb_unshare_pmd_ptdesc() function sets tlb->unshared_tables=true but the aarch64 tlb_flush() only checked tlb->freed_tables to determine whether to use TLBF_NONE (vae1is, invalidates walk cache) or TLBF_NOWALKCACHE (vale1is, leaf-only). This caused the stale PMD page table entry to remain in the walk cache after unshare, potentially leading to incorrect page table walks. Fix by including unshared_tables in the check, so that when unsharing tables, TLBF_NONE is used and the walk cache is properly invalidated. Here is the detailed distinction between vae1is and vale1is: | Instruction Combination | Actual Invalidation Scope | | ------------------------ | --------------------------------------------------| | `VAE1IS` + TTL=`0` | All entries at all levels (full invalidation) | | `VAE1IS` + TTL=`2` (L2) | Non-leaf at Level 0/1 + leaf at Level 2 | | `VALE1IS` + TTL=`0` | Leaf entries at all levels (non-leaf not cleared) | | `VALE1IS` + TTL=`2` (L2) | Leaf entry at Level 2 only |

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00176 7th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.259, 5.15.210, 6.1.176 +5Red Hat: 4 advisoriesRed Hat: 13 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux5.10.253 to before 5.10.259; 5.15.203 to before 5.15.210; 6.1.167 to before 6.1.176; 6.6.127 to before 6.6.143; 6.12.74 to before 6.12.93; 6.18.13 to before 6.18.355.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35Patch availableCNA
LinuxLinux6.19 and later5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1Patch availableCNA
  • Linux VendorLinux Affected 5.10.253 to before 5.10.259; 5.15.203 to before 5.15.210; 6.1.167 to before 6.1.176; 6.6.127 to before 6.6.143; 6.12.74 to before 6.12.93; 6.18.13 to before 6.18.35 Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35 Patch available CNA
  • Linux VendorLinux Affected 6.19 and later Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1 Patch available CNA

CPE configurations NVD · 8

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.10.253 to before 5.10.259; 5.15.203 to before 5.15.210; 6.1.167 to before 6.1.176; 6.6.127 to before 6.6.143; 6.12.74 to before 6.12.93; 6.18.13 to before 6.18.35; 6.19.1 to before 7.0.12VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.19:-:*:*:*:*:*:*6.19VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:*6.19 rc7VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.19:rc8:*:*:*:*:*:*6.19 rc8VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*7.1 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*7.1 rc2VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*7.1 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*7.1 rc4VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.10.253 to before 5.10.259; 5.15.203 to before 5.15.210; 6.1.167 to before 6.1.176; 6.6.127 to before 6.6.143; 6.12.74 to before 6.12.93; 6.18.13 to before 6.18.35; 6.19.1 to before 7.0.12 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.19:-:*:*:*:*:*:* Versions 6.19 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:* Versions 6.19 rc7 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.19:rc8:*:*:*:*:*:* Versions 6.19 rc8 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* Versions 7.1 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* Versions 7.1 rc2 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* Versions 7.1 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* Versions 7.1 rc4 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35
  • Fix · CNA Linux (Linux) Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1

Red Hat 4 advisories

  • RHSA-2026:94109 Released 2026-11-02 · Red Hat rating Critical
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) kernel-64k-debug-devel-5.14.0-427.161.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.161.1.el9_4, kernel-64k-devel-5.14.0-427.161.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool-7.3.0-427.161.1.el9_4, kernel-5.14.0-427.161.1.el9_4, kernel-64k-5.14.0-427.161.1.el9_4 +29
    • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt-5.14.0-427.161.1.el9_4, kernel-rt-core-5.14.0-427.161.1.el9_4, kernel-rt-debug-5.14.0-427.161.1.el9_4 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt-5.14.0-427.161.1.el9_4, kernel-rt-core-5.14.0-427.161.1.el9_4, kernel-rt-debug-5.14.0-427.161.1.el9_4 +11
  • RHSA-2026:72623 Released 2026-09-28 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.53.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.53.1.el9_8, kernel-64k-devel-5.14.0-687.53.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.53.1.el9_8, kernel-64k-5.14.0-687.53.1.el9_8, kernel-64k-core-5.14.0-687.53.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.53.1.el9_8, libperf-5.14.0-687.53.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.53.1.el9_8, kernel-rt-64k-5.14.0-687.53.1.el9_8, kernel-rt-64k-core-5.14.0-687.53.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.53.1.el9_8, kernel-rt-core-5.14.0-687.53.1.el9_8, kernel-rt-debug-5.14.0-687.53.1.el9_8 +9
  • RHSA-2026:72468 Released 2026-09-28 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.169.1.el8_10, kernel-4.18.0-553.169.1.el8_10, kernel-abi-stablelists-4.18.0-553.169.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.169.1.el8_10
Show 1 more Red Hat advisories
  • RHSA-2026:72467 Released 2026-09-28 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-core-4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-debug-4.18.0-553.169.1.rt7.510.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-core-4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-debug-4.18.0-553.169.1.rt7.510.el8_10 +7

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:72623
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:94109
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:72468
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:72623
Red Hat Enterprise Linux BaseOS E4S (v.9.4)Fixed RHSA-2026:94109
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:72468
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:72623
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2026:72467
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2026:72467
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:72623
Red Hat Enterprise Linux Real Time E4S (v.9.4)Fixed RHSA-2026:94109
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:72623
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)Fixed RHSA-2026:94109
Not affected: 3 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-63875
  2. 2026-10-03 Alias added: GHSA-h9hg-3wv2-x6j7
  3. 2026-10-16 CISA SSVC decision points changed
  4. 2026-10-19 Weakness changed · CISA ADP
  5. 2026-10-30 Weakness changed · NVD
  6. 2026-11-03 Fix available: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) +1 · Red Hat
  7. 2026-11-03 Fix available: RHSA-2026:94109 · Red Hat

References

Patch 8

  • 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-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
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences