5.5

CVE-2025-40300

x86/vmscape: Add conditional IBPB mitigation

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 ]
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 3.16.57 < 3.17
Linux ≫ Linux Kernel Version >= 4.4.168 < 4.5
Linux ≫ Linux Kernel Version >= 4.16 < 5.10.244
Linux ≫ Linux Kernel Version >= 5.11 < 5.15.193
Linux ≫ Linux Kernel Version >= 5.16 < 6.1.152
Linux ≫ Linux Kernel Version >= 6.2 < 6.6.106
Linux ≫ Linux Kernel Version >= 6.7 < 6.12.47
Linux ≫ Linux Kernel Version >= 6.13 < 6.16.7
Linux ≫ Linux Kernel Version6.17 Updaterc1
Linux ≫ Linux Kernel Version6.17 Updaterc2
Linux ≫ Linux Kernel Version6.17 Updaterc3
Linux ≫ Linux Kernel Version6.17 Updaterc4
Linux ≫ Linux Kernel Version6.17 Updaterc5
Debian ≫ Debian Linux Version11.0
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.33% 0.247
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 5.5 1.8 3.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Es wurden noch keine Informationen zu CWE veröffentlicht.
https://git.kernel.org/stable/c/ac60717f9a8d21c58617d0b34274babf24135835
Patch
https://git.kernel.org/stable/c/c08192b5d6730a914dee6175bc71092ee6a65f14
Patch
https://git.kernel.org/stable/c/d5490dfa35427a2967e00a4c7a1b95fdbc8ede34
Patch
https://git.kernel.org/stable/c/2f4f2f8f860cb4c3336a7435ebe8dcfded0c9c6e
Patch
https://git.kernel.org/stable/c/15006289e5c38b2a830e1fba221977a27598176c
Patch
https://git.kernel.org/stable/c/893387c18612bb452336a5881da0d015a7e8f4a2
Patch
https://git.kernel.org/stable/c/f866eef8d1c65504d30923c3f14082ad294d0e6d
Patch
https://git.kernel.org/stable/c/34e5667041050711a947e260fc9ebebe08bddee5
Patch
https://git.kernel.org/stable/c/d7ddc93392e4a7ffcccc86edf6ef3e64c778db52
Patch
https://git.kernel.org/stable/c/459274c77b37ac63b78c928b4b4e748d1f9d05c8
Patch
https://git.kernel.org/stable/c/510603f504796c3535f67f55fb0b124a303b44c8
Patch
https://git.kernel.org/stable/c/9c23a90648e831d611152ac08dbcd1283d405e7f
Patch
https://git.kernel.org/stable/c/2f8f173413f1cbf52660d04df92d0069c4306d25
Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
Third Party Advisory
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
Third Party Advisory
http://www.openwall.com/lists/oss-security/2025/11/14/3
Mailing List
http://www.openwall.com/lists/oss-security/2025/11/14/4
Mailing List
http://www.openwall.com/lists/oss-security/2025/11/14/6
Mailing List
http://www.openwall.com/lists/oss-security/2025/11/17/2
Mailing List
http://www.openwall.com/lists/oss-security/2025/11/17/3
Mailing List
https://cert-portal.siemens.com/productcert/html/ssa-032379.html