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TI-2025-26970 Aliases CVE-2025-40300GHSA-x8qw-46ww-c957

x86/vmscape: Add conditional IBPB mitigation

Priority LOW 25Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 37 fixed, 3 without a fix

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

Summary

In the Linux kernel, the following vulnerability has been resolved: x86/vmscape: Add conditional IBPB mitigation VMSCAPE is a vulnerability that exploits insufficient branch predictor isolation between a guest and a userspace hypervisor (like QEMU). Existing mitigations already protect kernel/KVM from a malicious guest. Userspace can additionally be protected by flushing the branch predictors after a VMexit. Since it is the userspace that consumes the poisoned branch predictors, conditionally issue an IBPB after a VMexit and before returning to userspace. Workloads that frequently switch between hypervisor and userspace will incur the most overhead from the new IBPB. This new IBPB is not integrated with the existing IBPB sites. For instance, a task can use the existing speculation control prctl() to get an IBPB at context switch time. With this implementation, the IBPB is doubled up: one at context switch and another before running userspace. The intent is to integrate and optimize these cases post-embargo. [ dhansen: elaborate on suboptimal IBPB solution ]

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00378 31st percentileScored 2026-11-07
Fix Partial Linux (Linux): 3.17, 4.5, 5.10.244 +6Red Hat: 13 advisoriesRed Hat: 37 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

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

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux3.16.57 to before 3.17; 4.4.168 to before 4.53.17, 4.5Patch availableCNA
LinuxLinux4.16 and later5.10.244, 5.15.193, 6.1.152, 6.6.106, 6.12.47, 6.16.7, 6.17Patch availableCNA
  • Linux VendorLinux Affected 3.16.57 to before 3.17; 4.4.168 to before 4.5 Fixed in 3.17, 4.5 Patch available CNA
  • Linux VendorLinux Affected 4.16 and later Fixed in 5.10.244, 5.15.193, 6.1.152, 6.6.106, 6.12.47, 6.16.7, 6.17 Patch available CNA

CPE configurations NVD · 7

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*3.16.57 to before 3.17; 4.4.168 to before 4.5; 4.16 to before 5.10.244; 5.11 to before 5.15.193; 5.16 to before 6.1.152; 6.2 to before 6.6.106; 6.7 to before 6.12.47; 6.13 to before 6.16.7VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*6.17 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*6.17 rc2VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*6.17 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*6.17 rc4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:*6.17 rc5VulnerableLinux
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*11.0VulnerableDebian
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.16.57 to before 3.17; 4.4.168 to before 4.5; 4.16 to before 5.10.244; 5.11 to before 5.15.193; 5.16 to before 6.1.152; 6.2 to before 6.6.106; 6.7 to before 6.12.47; 6.13 to before 6.16.7 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* Versions 6.17 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* Versions 6.17 rc2 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* Versions 6.17 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* Versions 6.17 rc4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* Versions 6.17 rc5 Vulnerable ·Linux
  • cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Versions 11.0 Vulnerable ·Debian

Remediation

  • Fix · CNA Linux (Linux) Fixed in 3.17, 4.5
  • Fix · CNA Linux (Linux) Fixed in 5.10.244, 5.15.193, 6.1.152, 6.6.106, 6.12.47, 6.16.7, 6.17

Red Hat 13 advisories

  • RHSA-2026:0271 Released 2026-01-08 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.52.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.52.1.el10_0, kernel-64k-devel-6.12.0-55.52.1.el10_0 +8
    • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.52.1.el10_0, kernel-64k-6.12.0-55.52.1.el10_0, kernel-64k-core-6.12.0-55.52.1.el10_0 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.52.1.el10_0
    • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.52.1.el10_0, kernel-rt-64k-6.12.0-55.52.1.el10_0, kernel-rt-64k-core-6.12.0-55.52.1.el10_0 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.52.1.el10_0, kernel-rt-core-6.12.0-55.52.1.el10_0, kernel-rt-debug-6.12.0-55.52.1.el10_0 +11
  • RHSA-2025:22124 Released 2025-11-25 · Red Hat rating Moderate
    kernel-rt security update
    • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt-5.14.0-284.148.1.rt14.433.el9_2, kernel-rt-core-5.14.0-284.148.1.rt14.433.el9_2, kernel-rt-debug-5.14.0-284.148.1.rt14.433.el9_2 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt-5.14.0-284.148.1.rt14.433.el9_2, kernel-rt-core-5.14.0-284.148.1.rt14.433.el9_2, kernel-rt-debug-5.14.0-284.148.1.rt14.433.el9_2 +11
  • RHSA-2025:22095 Released 2025-11-25 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) kernel-64k-debug-devel-5.14.0-284.148.1.el9_2, kernel-64k-debug-devel-matched-5.14.0-284.148.1.el9_2, kernel-64k-devel-5.14.0-284.148.1.el9_2 +10
    • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool-7.0.0-284.148.1.el9_2, kernel-5.14.0-284.148.1.el9_2, kernel-64k-5.14.0-284.148.1.el9_2 +29
Show 10 more Red Hat advisories
  • RHSA-2025:22087 Released 2025-11-25 · Red Hat rating Moderate
    kernel-rt security update
    • Red Hat Enterprise Linux NFV E4S (v.9.0) kernel-rt-5.14.0-70.155.1.rt21.227.el9_0, kernel-rt-core-5.14.0-70.155.1.rt21.227.el9_0, kernel-rt-debug-5.14.0-70.155.1.rt21.227.el9_0 +9
    • Red Hat Enterprise Linux Real Time E4S (v.9.0) kernel-rt-5.14.0-70.155.1.rt21.227.el9_0, kernel-rt-core-5.14.0-70.155.1.rt21.227.el9_0, kernel-rt-debug-5.14.0-70.155.1.rt21.227.el9_0 +7
  • RHSA-2025:22072 Released 2025-11-25 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux BaseOS E4S (v.8.8) bpftool-4.18.0-477.120.1.el8_8, kernel-4.18.0-477.120.1.el8_8, kernel-abi-stablelists-4.18.0-477.120.1.el8_8 +14
    • Red Hat Enterprise Linux BaseOS TUS (v.8.8) bpftool-4.18.0-477.120.1.el8_8, kernel-4.18.0-477.120.1.el8_8, kernel-abi-stablelists-4.18.0-477.120.1.el8_8 +14
  • RHSA-2025:22066 Released 2025-11-25 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.0) kernel-debug-devel-5.14.0-70.155.1.el9_0, kernel-debug-devel-matched-5.14.0-70.155.1.el9_0, kernel-devel-5.14.0-70.155.1.el9_0 +5
    • Red Hat Enterprise Linux BaseOS E4S (v.9.0) bpftool-5.14.0-70.155.1.el9_0, kernel-5.14.0-70.155.1.el9_0, kernel-abi-stablelists-5.14.0-70.155.1.el9_0 +14
  • RHSA-2025:22006 Released 2025-11-25 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux BaseOS AUS (v.8.6) bpftool-4.18.0-372.170.1.el8_6, kernel-4.18.0-372.170.1.el8_6, kernel-abi-stablelists-4.18.0-372.170.1.el8_6 +14
    • Red Hat Enterprise Linux BaseOS E4S (v.8.6) bpftool-4.18.0-372.170.1.el8_6, kernel-4.18.0-372.170.1.el8_6, kernel-abi-stablelists-4.18.0-372.170.1.el8_6 +19
    • Red Hat Enterprise Linux BaseOS TUS (v.8.6) bpftool-4.18.0-372.170.1.el8_6, kernel-4.18.0-372.170.1.el8_6, kernel-abi-stablelists-4.18.0-372.170.1.el8_6 +14
  • RHSA-2025:21760 Released 2025-11-19 · Red Hat rating Moderate
    kernel security update
    • Red Hat CodeReady Linux Builder EUS (v.9.4) kernel-tools-libs-devel-5.14.0-427.100.1.el9_4, libperf-5.14.0-427.100.1.el9_4
    • Red Hat Enterprise Linux AppStream EUS (v.9.4) kernel-64k-debug-devel-5.14.0-427.100.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.100.1.el9_4, kernel-64k-devel-5.14.0-427.100.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS EUS (v.9.4) bpftool-7.3.0-427.100.1.el9_4, kernel-5.14.0-427.100.1.el9_4, kernel-64k-5.14.0-427.100.1.el9_4 +29
    • Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt-5.14.0-427.100.1.el9_4, kernel-rt-core-5.14.0-427.100.1.el9_4, kernel-rt-debug-5.14.0-427.100.1.el9_4 +9
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4) kernel-rt-5.14.0-427.100.1.el9_4, kernel-rt-core-5.14.0-427.100.1.el9_4, kernel-rt-debug-5.14.0-427.100.1.el9_4 +11
  • RHSA-2025:21118 Released 2025-11-12 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-124.9.1.el10_1, kernel-64k-debug-devel-matched-6.12.0-124.9.1.el10_1, kernel-64k-devel-6.12.0-124.9.1.el10_1 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-124.9.1.el10_1, kernel-64k-6.12.0-124.9.1.el10_1, kernel-64k-core-6.12.0-124.9.1.el10_1 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-124.9.1.el10_1, libperf-6.12.0-124.9.1.el10_1
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-124.9.1.el10_1, kernel-rt-64k-6.12.0-124.9.1.el10_1, kernel-rt-64k-core-6.12.0-124.9.1.el10_1 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-124.9.1.el10_1, kernel-rt-core-6.12.0-124.9.1.el10_1, kernel-rt-debug-6.12.0-124.9.1.el10_1 +9
  • RHSA-2025:21112 Released 2025-11-12 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-611.7.1.el9_7, kernel-64k-debug-devel-matched-5.14.0-611.7.1.el9_7, kernel-64k-devel-5.14.0-611.7.1.el9_7 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-611.7.1.el9_7, kernel-64k-5.14.0-611.7.1.el9_7, kernel-64k-core-5.14.0-611.7.1.el9_7 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-611.7.1.el9_7, libperf-5.14.0-611.7.1.el9_7
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-611.7.1.el9_7, kernel-rt-64k-5.14.0-611.7.1.el9_7, kernel-rt-64k-core-5.14.0-611.7.1.el9_7 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-611.7.1.el9_7, kernel-rt-core-5.14.0-611.7.1.el9_7, kernel-rt-debug-5.14.0-611.7.1.el9_7 +9
  • RHSA-2025:19930 Released 2025-11-10 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-570.62.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.62.1.el9_6, kernel-64k-devel-5.14.0-570.62.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-570.62.1.el9_6, kernel-64k-5.14.0-570.62.1.el9_6, kernel-64k-core-5.14.0-570.62.1.el9_6 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-570.62.1.el9_6, libperf-5.14.0-570.62.1.el9_6
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-570.62.1.el9_6, kernel-rt-64k-5.14.0-570.62.1.el9_6, kernel-rt-64k-core-5.14.0-570.62.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-570.62.1.el9_6, kernel-rt-core-5.14.0-570.62.1.el9_6, kernel-rt-debug-5.14.0-570.62.1.el9_6 +11
  • RHSA-2025:19931 Released 2025-11-10 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.83.1.el8_10, kernel-4.18.0-553.83.1.el8_10, kernel-abi-stablelists-4.18.0-553.83.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.83.1.el8_10
  • RHSA-2025:19932 Released 2025-11-10 · Red Hat rating Moderate
    kernel-rt security update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.83.1.rt7.424.el8_10, kernel-rt-core-4.18.0-553.83.1.rt7.424.el8_10, kernel-rt-debug-4.18.0-553.83.1.rt7.424.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.83.1.rt7.424.el8_10, kernel-rt-core-4.18.0-553.83.1.rt7.424.el8_10, kernel-rt-debug-4.18.0-553.83.1.rt7.424.el8_10 +7

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat CodeReady Linux Builder EUS (v.9.4)Fixed RHSA-2025:21760
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2025:21118
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2025:19930, RHSA-2025:21112
Red Hat Enterprise Linux AppStream E4S (v.9.0)Fixed RHSA-2025:22066
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2025:22095
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:0271
Red Hat Enterprise Linux AppStream EUS (v.9.4)Fixed RHSA-2025:21760
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2025:21118
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2025:19931
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2025:19930, RHSA-2025:21112
Red Hat Enterprise Linux BaseOS AUS (v.8.6)Fixed RHSA-2025:22006
Red Hat Enterprise Linux BaseOS E4S (v.8.6)Fixed RHSA-2025:22006
Red Hat Enterprise Linux BaseOS E4S (v.8.8)Fixed RHSA-2025:22072
Red Hat Enterprise Linux BaseOS E4S (v.9.0)Fixed RHSA-2025:22066
Red Hat Enterprise Linux BaseOS E4S (v.9.2)Fixed RHSA-2025:22095
Red Hat Enterprise Linux BaseOS EUS (v. 10.0)Fixed RHSA-2026:0271
Red Hat Enterprise Linux BaseOS EUS (v.9.4)Fixed RHSA-2025:21760
Red Hat Enterprise Linux BaseOS TUS (v.8.6)Fixed RHSA-2025:22006
Red Hat Enterprise Linux BaseOS TUS (v.8.8)Fixed RHSA-2025:22072
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2025:19931
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2025:21118
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2025:19930, RHSA-2025:21112
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:0271
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2025:19932
Red Hat Enterprise Linux NFV E4S (v.9.0)Fixed RHSA-2025:22087
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2025:19932
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2025:21118
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2025:19930, RHSA-2025:21112
Red Hat Enterprise Linux Real Time E4S (v.9.0)Fixed RHSA-2025:22087
Red Hat Enterprise Linux Real Time E4S (v.9.2)Fixed RHSA-2025:22124
Red Hat Enterprise Linux Real Time EUS (v. 10.0)Fixed RHSA-2026:0271
Red Hat Enterprise Linux Real Time EUS (v.9.4)Fixed RHSA-2025:21760
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2025:21118
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2025:19930, RHSA-2025:21112
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2)Fixed RHSA-2025:22124
Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)Fixed RHSA-2026:0271
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4)Fixed RHSA-2025:21760
Not affected: 5 products
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0)
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0)
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-40300
  2. 2026-10-03 Alias added: GHSA-x8qw-46ww-c957

References

Patch 13

Advisory 2

  • 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

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