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CVE-2026-23553

In the context switch logic Xen attempts to skip an IBPB in the case of a vCPU returning to a CPU on which it was the previous vCPU to run. While safe for Xen's isolation between vCPUs, this prevents the guest kernel correctly isolating between tasks. Consider: 1) vCPU runs on CPU A, running task 1. 2) vCPU moves to CPU B, idle gets scheduled on A. Xen skips IBPB. 3) On CPU B, guest kernel switches from task 1 to 2, issuing IBPB. 4) vCPU moves back to CPU A. Xen skips IBPB again. Now, t
Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:c1e4dc4285937bb728c47ac0efad3327d116ebcd2621fc9dd88b58b605a813e1
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
1

Preserved source conflicts

No provider value was silently selected as the winner.

cwe · 2 assertions

{"cweId":"CWE-693","description":"CWE-693 Protection Mechanism Failure","lang":"en","type":"CWE"}

  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:702445e9566793bc78f5374bedb92ee0c408bde4fb0917b8a80735520b02aadd · sha256:bb0c6ca9752dbce9… · /containers/adp/1/problemTypes/1/descriptions/0

{"cweId":"CWE-665","description":"CWE-665 Improper Initialization","lang":"en","type":"CWE"}

  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:702445e9566793bc78f5374bedb92ee0c408bde4fb0917b8a80735520b02aadd · sha256:bb0c6ca9752dbce9… · /containers/adp/1/problemTypes/0/descriptions/0

Affected products and versions

1 source assertion
{"defaultStatus":"unknown","product":"Xen","vendor":"Xen","versions":[{"status":"unknown","version":"consult Xen advisory XSA-479"}]}
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:702445e9566793bc78f5374bedb92ee0c408bde4fb0917b8a80735520b02aadd · sha256:bb0c6ca9752dbce9… · /containers/cna/affected/0

Provider-owned CVSS observations

1 source assertion
{"metric":{"attackComplexity":"HIGH","attackVector":"LOCAL","availabilityImpact":"NONE","baseScore":2.9,"baseSeverity":"LOW","confidentialityImpact":"LOW","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:702445e9566793bc78f5374bedb92ee0c408bde4fb0917b8a80735520b02aadd · sha256:bb0c6ca9752dbce9… · /containers/adp/1/metrics/0/cvssV3_1

CWE assertions

2 source assertions
{"cweId":"CWE-693","description":"CWE-693 Protection Mechanism Failure","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:702445e9566793bc78f5374bedb92ee0c408bde4fb0917b8a80735520b02aadd · sha256:bb0c6ca9752dbce9… · /containers/adp/1/problemTypes/1/descriptions/0
{"cweId":"CWE-665","description":"CWE-665 Improper Initialization","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:702445e9566793bc78f5374bedb92ee0c408bde4fb0917b8a80735520b02aadd · sha256:bb0c6ca9752dbce9… · /containers/adp/1/problemTypes/0/descriptions/0

Source references

3 source assertions
{"url":"http://www.openwall.com/lists/oss-security/2026/01/27/3"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:702445e9566793bc78f5374bedb92ee0c408bde4fb0917b8a80735520b02aadd · sha256:bb0c6ca9752dbce9… · /containers/adp/0/references/0
{"url":"http://xenbits.xen.org/xsa/advisory-479.html"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:702445e9566793bc78f5374bedb92ee0c408bde4fb0917b8a80735520b02aadd · sha256:bb0c6ca9752dbce9… · /containers/adp/0/references/1
{"url":"https://xenbits.xenproject.org/xsa/advisory-479.html"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:702445e9566793bc78f5374bedb92ee0c408bde4fb0917b8a80735520b02aadd · sha256:bb0c6ca9752dbce9… · /containers/cna/references/0

Attribution and limitations

  • CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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