CVE-2026-23558 | grant table v2 race in status page mapping

The adjustments made for XSA-379 as well as those subsequently becoming XSA-387 still left a race window, when a HVM or PVH guest does a grant table version change from v2 to v1 in parallel with mapping the status page(s) via XENMEM_add_to_physmap. Some of the status pages may then be freed while mappings of them would still be inserted into the guest's secondary (P2M) page tables.

Published: 2026-05-19 Last update: 2026-05-19 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-23558 is rated Low Risk (31.6/100): CVSS High severity, with low exploitation likelihood (EPSS 0.01%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-23558

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-20 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-23558

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.1 6.0 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-23558

GitHub Security Advisory for CVE-2026-23558

GHSA-4qf9-g5cf-cx9j · Severity: high — The adjustments made for XSA-379 as well as those subsequently becoming XSA-387 still left a race...

OS Trackers for CVE-2026-23558

vendor priority summary link
debian end-of-life CVE-2026-23558 end-of-life priority: Debian including 1 source packages (xen), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. https://security-tracker.debian.org/tracker/CVE-2026-23558
suse high CVE-2026-23558 severity important: SUSE including 39 source package names (xen-4.12.4_66-3.140.1, xen-4.16.7_08-150400.4.81.2, …), 66 product×package rows across 15 product lines (SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS, SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS, … (15 product lines)): First Fixed 33, Fixed 33. https://www.suse.com/security/cve/CVE-2026-23558/
ubuntu medium CVE-2026-23558 medium priority: Ubuntu including 1 source packages (xen), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, upstream, xenial): needs-triage 8. https://ubuntu.com/security/CVE-2026-23558

Affected software / configurations for CVE-2026-23558

Vendor Product Version Raw CPE
xen xen >= 4.0.0 cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*

References for CVE-2026-23558

URL Tags
https://xenbits.xenproject.org/xsa/advisory-486.html Mitigation Patch Vendor Advisory
http://www.openwall.com/lists/oss-security/2026/04/28/13 Mailing List Mitigation Patch Third Party Advisory
http://xenbits.xen.org/xsa/advisory-486.html Mitigation Patch Vendor Advisory
cvelogic Threat Intelligence