CVE-2026-79611

MEDIUMPre-NVD 5.55.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 5.5 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit probability: 0.2% (5th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from CISA-ADP (Vulnrichment) CVSS v3.1
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS

Also known asEUVD-2026-98828 (ENISA EUVD) · GHSA-28w8-qvww-f539 (GitHub Security Advisories)Source: ENISA EUVD

5.5EG
EchelonGraph verdictMonitorNo fix is confirmed yet: check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.5Exploit: None knownExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

For XSA-308 logic was introduced, as VMX VMEntry checks do not like the exact combination of state which occurs when #DB in intercepted, Single Stepping is active, and blocked by STI/MovSS is active, despite this being a legitimate state to be in. The resulting VMEntry failure is fatal to the guest.

Sadly there is another special sub-case of the above, with branch tracing enabled. In that case the prior adjustment would still cause a VMentry failure, as before fatal to the guest.

CVSS v3
5.5
EG Score
5.5MEDIUMmedium confidence
EG Risk
25
EG Risk 25/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity55% × 45%
Impact severity (EG Severity): CVSS 5.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.
EPSS PROB
0.2%
EPSS %ILE
5th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.

EG Severity
5.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.CISA-ADP (Vulnrichment) CVSS v3.1 · CVSS v3.1
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS. FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

October 13, 2026

Last Modified

October 20, 2026

Advisory Details (3)

Auto-updated Oct 20, 2026
No fix on record yet.
Web page

oss-security - Xen Security Advisory 518 v2 (CVE-2026-79611) - VMX: VMentry failure with branch tracing and blocked states

http://www.openwall.com/lists/oss-security/2026/10/13/7
Web page

XSA-518 - Xen Security Advisories

http://xenbits.xen.org/xsa/advisory-518.html
Web page

XSA-518 - Xen Security Advisories

https://xenbits.xenproject.org/xsa/advisory-518.html

Vendor Advisories for CVE-2026-79611(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 32× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  2. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  3. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  4. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  5. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  6. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  7. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  8. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  9. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  10. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  11. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  12. 2026-10-25 13:59 UTCEG score recompute
  13. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  14. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  15. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  16. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  17. 2026-10-20 18:27 UTCGHSA enrichmentGHSA-28w8-qvww-f539
  18. 2026-10-20 17:48 UTCEG score recomputeFirst assessed: 5.5 MEDIUM
  19. 2026-10-20 17:48 UTCGHSA enrichmentGHSA-28w8-qvww-f539
  20. 2026-10-20 17:46 UTCMITRE cvelistV5CVSS v3 → 5.5 · severity → MEDIUM
  21. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  22. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  23. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  24. 2026-10-18 03:10 UTCEG score recompute
  25. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.2% · 5th percentile
Show 7 more
  1. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  2. 2026-10-14 18:46 UTCEG score recompute
  3. 2026-10-14 18:45 UTCGHSA enrichmentGHSA-28w8-qvww-f539
  4. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  5. 2026-10-13 16:25 UTCNVD update
  6. 2026-10-13 15:56 UTCEG score recompute
  7. 2026-10-13 15:54 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-79611?
CVE-2026-79611 is a medium-severity vulnerability; its CVE record was published on October 13, 2026. For XSA-308 logic was introduced, as VMX VMEntry checks do not like the exact combination of state which occurs when #DB in intercepted, Single Stepping is active, and blocked by STI/MovSS is active, despite this being a legitimate state to be in. The resulting VMEntry failure is fatal to the…
When was CVE-2026-79611 made public?
CVE-2026-79611 was made public on October 13, 2026: that is the date its CVE record's CNA, Xen Project, gives for when the vulnerability was made public. The CVE record itself was published on October 13, 2026. EchelonGraph's copy of the record carries a last-modified date of October 20, 2026; the record at its source may have been updated since.
Is CVE-2026-79611 actively exploited?
CVE-2026-79611 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (5th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-79611?
CVE-2026-79611 has a CVSS v3.1 base score of 5.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-79611?
No fix for CVE-2026-79611 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-79611 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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