Medium

CVE-2026-23215 — x86/vmware: Fix hypercall clobbers

In the Linux kernel, the following vulnerability has been resolved: x86/vmware: Fix hypercall clobbers Fedora QA reported the following panic: BUG: unable to handle page fault for address: 0000000040003e54 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20251119-3.fc43 11/19/2025 RIP: 0010:vmware_hypercall4.constprop.0+0x52/0x90 .. Call Trace: vmmouse_report_events+0x13e/0x1b0 psmouse_handle_byte+0x15/0x60 ps2_interrupt+0x8a/0xd0 ... because the QEMU VMware mouse emulation is buggy, and clears the top 32 bits of %rdi that the kernel kept a pointer in. The QEMU vmmouse driver saves and restores the register state in a "uint32_t data[6];" and as a result restores the state with the high bits all cleared. RDI originally contained the value of a valid kernel stack address (0xff5eeb3240003e54). After the vmware hypercall it now contains 0x40003e54, and we get a page fault as a result when it is dereferenced. The proper fix would be in QEMU, but this works around the issue in the kernel to keep old setups working, when old kernels had not happened to keep any state in %rdi over the hypercall. In theory this same issue exists for all the hypercalls in the vmmouse driver; in practice it has only been seen with vmware_hypercall3() and vmware_hypercall4(). For now, just mark RDI/RSI as clobbered for those two calls. This should have a minimal effect on code generation overall as it should be rare for the compiler to want to make RDI/RSI live across hypercalls.

Published Feb 18, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.1% (30-day exploitation probability)+0
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.12%

ahead of 2% of scored CVEs · Oct 14, 2026

Affects

Linux

Linux and 1 more

CVSS base

5.5

Medium · 1 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ 34bf25e820ae1ab38f9cd88834843ba76678a2fd and < 2f467a92df61eb516a4ec36ee16234dd4e5ccf00≥ 34bf25e820ae1ab38f9cd88834843ba76678a2fd and < feb603a69f830acb58f78d604f0c29e63cd38f87≥ 34bf25e820ae1ab38f9cd88834843ba76678a2fd and < 2687c848e57820651b9f69d30c4710f4219f7dbfversion 6.11	Vulnerable	CVE Program (cve.org) e CISA ADP
Linux	Linux Kernel	≥ 6.11 and < 6.12.70≥ 6.13 and < 6.18.10version 6.19-rc1version 6.19-rc2version 6.19-rc3version 6.19-rc4version 6.19-rc5version 6.19-rc6 and 2 more version 6.19-rc7version 6.19-rc8	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
5.5	CVSS 3.1	Medium	1.8	3.6	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov)

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.12%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.

endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 5.5
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Feb 18, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

3 on the record

git.kernel.org/stable/c/2f467a92df61eb516a4ec36ee16234dd4e5ccf00
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/2687c848e57820651b9f69d30c4710f4219f7dbf
Patch, NIST National Vulnerability Database
git.kernel.org/stable/c/feb603a69f830acb58f78d604f0c29e63cd38f87
Patch, NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 13h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 13h
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-23215 is "x86/vmware: Fix hypercall clobbers", rated Medium. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 describes technical severity. EPSS 0.12% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.