VulnerabilityPublished 27 May 2026Updated 21 Oct 2026

CVE-2026-46014: Linux kernel · KVM: SVM: Add missing save/restore handling of LBR MSRs

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in bca0597272f9712b1f8ebd38b184db1dc2902ff7 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.09% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in bca0597272f9712b1f8ebd38b184db1dc2902ff7, 4428a0a8643b0acf4ed7b8ea3e5975023bf4aafb, 3700f0788da6acf73b2df56690f4b201aa4aefd2 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 27 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 24e09cbf480a72f9c952af4ca77b159503dca44b, < bca0597272f9712b1f8ebd38b184db1dc2902ff7	Fixed in bca0597272f9712b1f8ebd38b184db1dc2902ff7
LinuxLinux	Affected ≥ 24e09cbf480a72f9c952af4ca77b159503dca44b, < 4428a0a8643b0acf4ed7b8ea3e5975023bf4aafb	Fixed in 4428a0a8643b0acf4ed7b8ea3e5975023bf4aafb
LinuxLinux	Affected ≥ 24e09cbf480a72f9c952af4ca77b159503dca44b, < 3700f0788da6acf73b2df56690f4b201aa4aefd2	Fixed in 3700f0788da6acf73b2df56690f4b201aa4aefd2
LinuxLinux	Affected ≥ 24e09cbf480a72f9c952af4ca77b159503dca44b, < 13a89ada5dcfc2539514c83ba5a2c61157f1ec6c	Fixed in 13a89ada5dcfc2539514c83ba5a2c61157f1ec6c
LinuxLinux	Affected ≥ 24e09cbf480a72f9c952af4ca77b159503dca44b, < 2b922a42b531a82d7881add14a7698dcdc5e1f0a	Fixed in 2b922a42b531a82d7881add14a7698dcdc5e1f0a
LinuxLinux	Affected =2.6.26	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Add missing save/restore handling of LBR MSRs MSR_IA32_DEBUGCTLMSR and LBR MSRs are currently not enumerated by KVM_GET_MSR_INDEX_LIST, and LBR MSRs cannot be set with KVM_SET_MSRS. So save/restore is completely broken. Fix it by adding the MSRs to msrs_to_save_base, and allowing writes to LBR MSRs from userspace only (as they are read-only MSRs) if LBR virtualization is enabled. Additionally, to correctly restore L1's LBRs while L2 is running, make sure the LBRs are copied from the captured VMCB01 save area in svm_copy_vmrun_state(). Note, for VMX, this also fixes a flaw where MSR_IA32_DEBUGCTLMSR isn't reported as an MSR to save/restore. Note #2, over-reporting MSR_IA32_LASTxxx on Intel is ok, as KVM already handles unsupported reads and writes thanks to commit b5e2fec0ebc3 ("KVM: Ignore DEBUGCTL MSRs with no effect") (kvm_do_msr_access() will morph the unsupported userspace write into a nop). [sean: guard with lbrv checks, massage changelog]

References

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