[UPDATE] [medium] Xen: Vulnerability allows bypassing security measures

mediumCVE-2026-31788

A local attacker from a guest VM can exploit a vulnerability in Xen to bypass security measures.

CSIRTS triage

vendor: Xen product: Xen Authentication bypass

What: A vulnerability in Xen allows a local attacker from a guest VM to bypass security measures.
Who is affected: Local attackers with access to a guest VM can exploit this vulnerability.
Urgency: Remediation is medium urgency due to the potential for security measure bypass.
Action: Apply the latest security updates for Xen.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CERT-Bund (BSI) Security Advisories (DE · national-cert · site)
Severity: medium
Published: 2026-07-07
Exploitation: Not in CISA KEV at last sync
Language: Machine-translated to English — verify against the original

Original advisory: https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-0855

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-317880.15% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 5% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-31788	coverage & exploitation status	NVD · CVE.org

Recent advisories for Xen

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

medium[UPDATE] [medium] Xen: Multiple vulnerabilitiescert-bund · 2026-07-10
high[UPDATE] [high] Xen and Citrix Systems XenServer: Multiple vulnerabilitiescert-bund · 2026-07-10
high[UPDATE] [high] Xen: Multiple vulnerabilitiescert-bund · 2026-07-10
low[UPDATE] [low] AMD Processors and Xen: Vulnerability allows information disclosurecert-bund · 2026-07-02