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Xen Hypervisor CVE-2026-23558

| EUVDEUVD-2026-30928 HIGH
Race Condition (CWE-362)
2026-05-08 GHSA-4qf9-g5cf-cx9j
Linux Buffer Overflow Race Condition Xen
7.8
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
7.8 HIGH
AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
vuln.today AI
7.8 HIGH

A hostile guest (PR:L, AV:L) must win a hard-to-hit race (AC:H); success escapes to the hypervisor (S:C) with full host CIA impact.

3.1 AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
4.0 AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
SUSE
HIGH
qualitative

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

3
Analysis Generated
Jul 23, 2026 - 22:56 vuln.today
CVE Published
May 08, 2026 - 06:45 oss-security
HIGH 7.8
CVE Published
May 08, 2026 - 06:45 nvd
UNKNOWN (no severity yet)

Description PRE-NVD

Disclosed via oss-security. NVD scoring and full description are pending.

AnalysisAI

Privilege escalation and host compromise in the Xen hypervisor arises from a race condition (XSA-486) in grant table v2 status page mapping, where concurrent operations on the shared grant status frame can be exploited by a malicious or buggy guest to corrupt host memory state. A cooperating pair of guests (or a guest coordinating grant operations) can win the race to gain confidentiality, integrity, and availability impact that crosses the guest/host boundary (scope change). There is no public exploit identified at time of analysis, and the EPSS probability is negligible (0.01%), consistent with a high-complexity, local-only race that is difficult to weaponize.

Technical ContextAI

Xen's grant table mechanism lets a guest domain grant another domain controlled access to specific memory pages, forming the backbone of paravirtualized I/O (block/network rings) and inter-domain sharing. Grant table version 2 introduces a separate 'status' page that tracks the in-use state of grants independently from the grant entries themselves. XSA-486 concerns a race (CWE-362, concurrent execution using shared resource with improper synchronization) in how the hypervisor maps and manages this v2 status page: overlapping map/unmap or version-switch operations lack sufficient synchronization, so a time-of-check to time-of-use window allows a guest to manipulate the mapping while the hypervisor operates on it. Because the affected code runs in the hypervisor on behalf of the guest, successful exploitation escapes guest isolation. The CPE cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:* identifies the Xen hypervisor itself (all versions supporting grant table v2) as the affected component.

RemediationAI

Apply the vendor-supplied fix from Xen Security Advisory 486 (https://xenbits.xenproject.org/xsa/advisory-486.html); a patch is available per vendor advisory, though this data set does not contain a single exact upstream release tag, so confirm the fixed version against the XSA-486 patch series for your Xen branch. On SUSE systems, update to the fixed hypervisor packages delivered in SUSE-SU-2026:1645, 1657, 1692, 1743, or 1998 (https://www.suse.com/support/update/SUSE-SU-2026:1645/) and reboot into the patched hypervisor. If immediate patching is not possible, reduce exposure by limiting which untrusted or multi-tenant guests run on affected hosts and, where operationally feasible, avoid or restrict grant table v2 usage for untrusted domains - with the trade-off that some PV/PVH drivers and guests rely on v2 semantics, so forcing v1 or restricting grant operations may break device functionality and should be tested first. Because exploitation requires a hostile local guest, tightening guest admission (trusted tenants only) is an effective compensating control until the hypervisor is patched.

More in Xen

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CVE-2012-0217 HIGH POC
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The x86-64 kernel system-call functionality in Xen 4.1.2 and earlier, as used in Citrix XenServer 6.0.2 and earlier and

CVE-2015-3456 HIGH POC
7.7 May 13

The Floppy Disk Controller (FDC) in QEMU, as used in Xen 4.5.x and earlier and KVM, allows local guest users to cause a

CVE-2018-8897 HIGH POC
7.8 May 08

A statement in the System Programming Guide of the Intel 64 and IA-32 Architectures Software Developer's Manual (SDM) wa
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8.8 Jun 07

The AdSanity plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the 'aj
CVE-2017-15595 HIGH POC
8.8 Oct 18

An issue was discovered in Xen through 4.9.x allowing x86 PV guest OS users to cause a denial of service (unbounded recu
CVE-2017-7228 HIGH POC
8.2 Apr 04

An issue (known as XSA-212) was discovered in Xen, with fixes available for 4.8.x, 4.7.x, 4.6.x, 4.5.x, and 4.4.x. Rated
CVE-2015-5165 CRITICAL
9.3 Aug 12

The C+ mode offload emulation in the RTL8139 network card device model in QEMU, as used in Xen 4.5.x and earlier, allows
CVE-2015-8550 HIGH
8.2 Apr 14

Xen, when used on a system providing PV backends, allows local guest OS administrators to cause a denial of service (hos
CVE-2022-26364 MEDIUM POC
6.7 Jun 09

x86 pv: Insufficient care with non-coherent mappings T[his CNA information record relates to multiple CVEs; the text exp
CVE-2017-10918 CRITICAL
10.0 Jul 05

Xen through 4.8.x does not validate memory allocations during certain P2M operations, which allows guest OS users to obt
CVE-2017-10912 CRITICAL
10.0 Jul 05

Xen through 4.8.x mishandles page transfer, which allows guest OS users to obtain privileged host OS access, aka XSA-217
CVE-2017-10921 CRITICAL
10.0 Jul 05

The grant-table feature in Xen through 4.8.x does not ensure sufficient type counts for a GNTMAP_device_map and GNTMAP_h

Same weakness CWE-362 – Race Condition

View all
CVE-2023-36884 HIGH POC
7.5
CVE-2016-5195 HIGH POC
7.0
CVE-2017-1000112 HIGH POC
7.0
CVE-2014-0196 MEDIUM POC
5.5
CVE-2014-0226 MEDIUM POC
6.8
CVE-2016-1757 HIGH POC
7.0
CVE-2016-8655 HIGH POC
7.8
CVE-2015-5754 CRITICAL POC
9.3

Same technique Buffer Overflow

View all
CVE-2017-7269 CRITICAL POC
9.8
CVE-2015-5119 CRITICAL POC
9.8
CVE-2015-3113 CRITICAL POC
9.8
CVE-2011-2462 CRITICAL POC
9.8
CVE-2020-0796 CRITICAL POC
10.0
CVE-2019-11043 CRITICAL POC
9.8
CVE-2009-0927 HIGH POC
8.8
CVE-2012-1889 HIGH POC
8.8

Vendor StatusVendor

SUSE

Severity: High
Product Status
Image SLES15-SP4-BYOS-Azure Image SLES15-SP4-BYOS-GCE Image SLES15-SP4-CHOST-BYOS-Aliyun Image SLES15-SP4-CHOST-BYOS-Azure Image SLES15-SP4-CHOST-BYOS-GCE Image SLES15-SP4-CHOST-BYOS-SAP-CCloud Image SLES15-SP4-HPC-BYOS Image SLES15-SP4-HPC-BYOS-Azure Image SLES15-SP4-HPC-BYOS-GCE Image SLES15-SP4-HPC-GCE Image SLES15-SP4-Hardened-BYOS-Azure Image SLES15-SP4-Hardened-BYOS-GCE Image SLES15-SP4-SAP-Azure Image SLES15-SP4-SAP-BYOS-Azure Image SLES15-SP4-SAP-BYOS-GCE Image SLES15-SP4-SAP-GCE Image SLES15-SP4-SAP-Hardened Image SLES15-SP4-SAP-Hardened-Azure Image SLES15-SP4-SAP-Hardened-BYOS Image SLES15-SP4-SAP-Hardened-BYOS-Azure Image SLES15-SP4-SAP-Hardened-BYOS-GCE Image SLES15-SP4-SAP-Hardened-GCE Image SLES15-SP4-SAPCAL-Azure Image SLES15-SP4-SAPCAL-GCE Affected
Image SLES15-SP4-BYOS Image SLES15-SP4-BYOS-EC2 Image SLES15-SP4-CHOST-BYOS Image SLES15-SP4-CHOST-BYOS-EC2 Image SLES15-SP4-HPC-BYOS-EC2 Image SLES15-SP4-HPC-EC2 Image SLES15-SP4-Hardened-BYOS Image SLES15-SP4-Hardened-BYOS-EC2 Image SLES15-SP4-SAP Image SLES15-SP4-SAP-BYOS Image SLES15-SP4-SAP-BYOS-EC2 Image SLES15-SP4-SAP-EC2 Image SLES15-SP4-SAP-Hardened-BYOS-EC2 Image SLES15-SP4-SAPCAL Image SLES15-SP4-SAPCAL-EC2 Affected
Image SLES15-SP5-BYOS-Azure Image SLES15-SP5-BYOS-GCE Image SLES15-SP5-CHOST-BYOS-Aliyun Image SLES15-SP5-CHOST-BYOS-Azure Image SLES15-SP5-CHOST-BYOS-GCE Image SLES15-SP5-CHOST-BYOS-GDC Image SLES15-SP5-CHOST-BYOS-SAP-CCloud Image SLES15-SP5-GCE Image SLES15-SP5-HPC-BYOS-Azure Image SLES15-SP5-HPC-BYOS-GCE Image SLES15-SP5-Hardened-BYOS-Azure Image SLES15-SP5-Hardened-BYOS-GCE Image SLES15-SP5-SAP-Azure-3P Image SLES15-SP5-SAP-BYOS-Azure Image SLES15-SP5-SAP-BYOS-GCE Image SLES15-SP5-SAP-Hardened-Azure Image SLES15-SP5-SAP-Hardened-BYOS-Azure Image SLES15-SP5-SAP-Hardened-BYOS-GCE Image SLES15-SP5-SAP-Hardened-GCE Image SLES15-SP5-SAPCAL-Azure Image SLES15-SP5-SAPCAL-GCE Affected
Image SLES15-SP5-BYOS-EC2 Image SLES15-SP5-CHOST-BYOS-EC2 Image SLES15-SP5-EC2 Image SLES15-SP5-HPC-BYOS-EC2 Image SLES15-SP5-Hardened-BYOS-EC2 Image SLES15-SP5-SAP-BYOS-EC2 Image SLES15-SP5-SAP-Hardened-BYOS-EC2 Image SLES15-SP5-SAPCAL-EC2 Affected
Image SLES15-SP7-Azure-3P Image SLES15-SP7-Azure-Basic Image SLES15-SP7-Azure-Standard Image SLES15-SP7-BYOS-Azure Image SLES15-SP7-BYOS-GCE Image SLES15-SP7-CHOST-BYOS-Aliyun Image SLES15-SP7-CHOST-BYOS-Azure Image SLES15-SP7-CHOST-BYOS-GCE Image SLES15-SP7-CHOST-BYOS-GDC Image SLES15-SP7-CHOST-BYOS-SAP-CCloud Image SLES15-SP7-GCE Image SLES15-SP7-GCE-3P Image SLES15-SP7-HPC-BYOS-Azure Image SLES15-SP7-HPC-BYOS-GCE Image SLES15-SP7-Hardened-BYOS-Azure Image SLES15-SP7-Hardened-BYOS-GCE Image SLES15-SP7-SAP-Azure Image SLES15-SP7-SAP-Azure-3P Image SLES15-SP7-SAP-BYOS-Azure Image SLES15-SP7-SAP-BYOS-GCE Image SLES15-SP7-SAP-GCE Image SLES15-SP7-SAP-GCE-3P Image SLES15-SP7-SAP-Hardened-Azure Image SLES15-SP7-SAP-Hardened-BYOS-Azure Image SLES15-SP7-SAP-Hardened-BYOS-GCE Image SLES15-SP7-SAP-Hardened-GCE Image SLES15-SP7-SAPCAL-Azure Image SLES15-SP7-SAPCAL-GCE Affected

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CVE-2026-23558 vulnerability details – vuln.today
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