CVE-2025-40300

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Source
https://cve.org/CVERecord?id=CVE-2025-40300
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40300.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2025-40300
Downstream
AZL (2)
BELL (1)
DEBIAN (1)
ECHO (1)
MGASA (2)
OESA (3)
openSUSE (4)
RHSA (13)
RLSA (2)
ROOT (5)
SUSE (19)
UBUNTU (1)
Related
ALSA (3)
openSUSE (4)
SUSE (19)
Published
2025-09-11T16:49:24Z
Modified
2026-10-20T10:30:30Z
Summary
x86/vmscape: Add conditional IBPB mitigation
Details

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 ]

Database specific 
{
    "cna_assigner":  "Linux",
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40300.json"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
15d45071523d89b3fb7372e2135fbd72f6af9506
Fixed
ac60717f9a8d21c58617d0b34274babf24135835
Fixed
c08192b5d6730a914dee6175bc71092ee6a65f14
Fixed
d5490dfa35427a2967e00a4c7a1b95fdbc8ede34
Fixed
2f4f2f8f860cb4c3336a7435ebe8dcfded0c9c6e
Fixed
15006289e5c38b2a830e1fba221977a27598176c
Fixed
893387c18612bb452336a5881da0d015a7e8f4a2
Fixed
f866eef8d1c65504d30923c3f14082ad294d0e6d
Fixed
34e5667041050711a947e260fc9ebebe08bddee5
Fixed
d7ddc93392e4a7ffcccc86edf6ef3e64c778db52
Fixed
459274c77b37ac63b78c928b4b4e748d1f9d05c8
Fixed
510603f504796c3535f67f55fb0b124a303b44c8
Fixed
9c23a90648e831d611152ac08dbcd1283d405e7f
Fixed
2f8f173413f1cbf52660d04df92d0069c4306d25
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
3.16.57
Fixed
3.17
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
4.4.168
Fixed
4.5
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
c51f1e5f57cca88d8d5894b6fad1638f643a99d0
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
4b3870c343a82cd2df7192cc5149c87205dcc611

Affected versions

v3.*
v3.16.57
v3.16.58
v3.16.59
v3.16.60
v3.16.61
v3.16.62
v3.16.63
v3.16.64
v3.16.65
v3.16.66
v3.16.67
v3.16.68
v3.16.69
v3.16.70
v3.16.71
v3.16.72
v3.16.73
v3.16.74
v3.16.75
v3.16.76
v3.16.77
v3.16.78
v3.16.79
v3.16.80
v3.16.81
v3.16.82
v3.16.83
v3.16.84
v3.16.85
v4.*
v4.4.168
v4.4.169
v4.4.170
v4.4.171
v4.4.172
v4.4.173
v4.4.174
v4.4.175
v4.4.176
v4.4.177
v4.4.178
v4.4.179
v4.4.180
v4.4.181
v4.4.182
v4.4.183
v4.4.184
v4.4.185
v4.4.186
v4.4.187
v4.4.188
v4.4.189
v4.4.190
v4.4.191
v4.4.192
v4.4.193
v4.4.194
v4.4.195
v4.4.196
v4.4.197
v4.4.198
v4.4.199
v4.4.200
v4.4.201
v4.4.202
v4.4.203
v4.4.204
v4.4.205
v4.4.206
v4.4.207
v4.4.208
v4.4.209
v4.4.210
v4.4.211
v4.4.212
v4.4.213
v4.4.214
v4.4.215
v4.4.216
v4.4.217
v4.4.218
v4.4.219
v4.4.220
v4.4.221
v4.4.222
v4.4.223
v4.4.224
v4.4.225
v4.4.226
v4.4.227
v4.4.228
v4.4.229
v4.4.230
v4.4.231
v4.4.232
v4.4.233
v4.4.234
v4.4.235
v4.4.236
v4.4.237
v4.4.238
v4.4.239
v4.4.240
v4.4.241
v4.4.242
v4.4.243
v4.4.244
v4.4.245
v4.4.246
v4.4.247
v4.4.248
v4.4.249
v4.4.250
v4.4.251
v4.4.252
v4.4.253
v4.4.254
v4.4.255
v4.4.256
v4.4.257
v4.4.258
v4.4.259
v4.4.260
v4.4.261
v4.4.262
v4.4.263
v4.4.264
v4.4.265
v4.4.266
v4.4.267
v4.4.268
v4.4.269
v4.4.270
v4.4.271
v4.4.272
v4.4.273
v4.4.274
v4.4.275
v4.4.276
v4.4.277
v4.4.278
v4.4.279
v4.4.280
v4.4.281
v4.4.282
v4.4.283
v4.4.284
v4.4.285
v4.4.286
v4.4.287
v4.4.288
v4.4.289
v4.4.290
v4.4.291
v4.4.292
v4.4.293
v4.4.294
v4.4.295
v4.4.296
v4.4.297
v4.4.298
v4.4.299
v4.4.300
v4.4.301
v4.4.302

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40300.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
4.16.0
Fixed
5.10.244
Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.193
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.152
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.106
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.12.47
Type
ECOSYSTEM
Events
Introduced
6.13.0
Fixed
6.16.7

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40300.json"