Loading vulnerability…
CVE-2026-23556 is a denial-of-service vulnerability in Xen's oxenstored implementation. When oxenstored tears down a domain, it correctly removes the domain's xenstore node data but fails to clear the associated quota usage counters. If that domain identifier is later reused, the newly created domain inherits stale accounting state and is considered closer to its xenstore quota than it should be. As leaked counts accumulate across repeated domain destruction and ID reuse, affected domains can create progressively fewer xenstore nodes and may eventually be unable to operate normally. The issue affects Xen environments using oxenstored, including XAPI oxenstored, while systems using the C-based xenstored implementation are not affected. Xen advisory material states the vulnerable set includes Xen versions containing the XSA-419 fixes when configured to use oxenstored.
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
If you can’t patch tonight, do this now.
Patch, then assume compromise.
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
12 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A vulnerability in oxenstored involving leaked quota counters on domain destruction and ID reuse, leading primarily to denial of service affecting VM startup.
A vulnerability in Xen oxenstored where usage counts are leaked during domain teardown, causing a reused domain ID to inherit reduced node quota availability.
A Citrix-addressed vulnerability listed in the July 1, 2026 security updates affecting Citrix products; specific technical details are not provided in the content.
A flaw in oxenstored where quota-related use counts persist across domain destruction, enabling a privileged guest-domain user to cause denial of service by preventing other domains from starting.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.