Vulnerability · Published Jun 18, 2026 · Assigned by XEN
CVE-2026-42488x86: mismatched mapcache metadata
High 8.1
In plain English
A high-severity memory corruption in Xen from Xen. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 29% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.4%top 70.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Some shadow paging errors paths will switch the page-tables without updating the currently running vCPU reference. This causes a mismatch between the loaded page-tables and the mapcache metadata which can lead to corruption of the mapcache.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | xen | 4.18.5-r9 | ALPINE-CVE-2026-42488 |
| Alpine:v3.21 | xen | 4.19.5-r4 | ALPINE-CVE-2026-42488 |
| Alpine:v3.22 | xen | 4.20.3-r4 | ALPINE-CVE-2026-42488 |
| Alpine:v3.23 | xen | 4.20.3-r4 | ALPINE-CVE-2026-42488 |
| Alpine:v3.24 | xen | 4.21.1-r6 | ALPINE-CVE-2026-42488 |
| Debian:12 | xen | 4.17.7-0+deb12u1 | DEBIAN-CVE-2026-42488 |
| Debian:13 | xen | 4.20.3+127-gc42374a105-0+deb13u1 | DEBIAN-CVE-2026-42488 |
| Debian:14 | xen | 4.20.3+127-gc42374a105-1 | DEBIAN-CVE-2026-42488 |
| Ubuntu:22.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-42488 |
| Ubuntu:24.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-42488 |
| Ubuntu:25.10 | xen | no fix listed | UBUNTU-CVE-2026-42488 |
| Ubuntu:26.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-42488 |
| Ubuntu:26.10 | xen | no fix listed | UBUNTU-CVE-2026-42488 |
Affected products (as reported)
Weakness: CWE-119 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H