CVE-2026-42490: domctl lock open to abuse
Vulnerability summary
CVE-2026-42490 is a medium (CVSS 6.5) Improper Locking vulnerability in xen. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 9.8% of scored vulnerabilities.
Not severe (CVSS 6.5, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 5 · Related 5Timeline
- 18-06-2026PublishedVulnerability first disclosed.
- 18-06-2026Last modifiedVulnerability information updated.
Description
[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] To create and manage guests, domctl operations are used by the control domain, a possible Xenstore domain, or by a domain controlling a particular guest. Some of these operations may not be executed in parallel, so a system-wide lock is used. The way that lock is acquired is, however, not providing any fairness. This is CVE-2026-42489. Furthermore, with XSM/Flask in use, the lock acquire will, for some operations, occur ahead of any permission checking. This is CVE-2026-42490.
CVSS metrics
5 scores · 5 sources · 1 version- OSV · AlpineEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- NVDNIST6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.20%
Chance of exploitation in the next 30 days
Percentile
10%
Versus all other CVEs
30-day change
Decrease -0.12 pp
From 0.32% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Alpine1 product
- xen< 4.18.5-r9 | < 4.19.5-r4 | < 4.20.3-r4 | < 4.21.1-r6
Debian1 product
- xen< 4.17.7-0+deb12u1 | < 4.20.3+127-gc42374a105-0+deb13u1 | < 4.20.3+127-gc42374a105-1
Ubuntu1 product
- xenAll versions (No fix recorded)
3 vendors · 3 products
