CVE-2021-28697

HIGHNVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
7.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.8Exploit: NoneExposed: 0

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

grant table v2 status pages may remain accessible after de-allocation Guest get permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, get de-allocated when a guest switched (back) from v2 to v1. The freeing of such pages requires that the hypervisor know where in the guest these pages were mapped. The hypervisor tracks only one use within guest space, but racing requests from the guest to insert mappings of these pages may result in any of them to become mapped in multiple locations. Upon switching back from v2 to v1, the guest would then retain access to a page that was freed and perhaps re-used for other purposes.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
17.9%
KEV
Not listed

Published

August 27, 2021

Last Modified

November 21, 2024

References (12)

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 50× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 102 total refreshes for this CVE.

  1. 2026-07-23 14:16 UTCEPSS rescore
  2. 2026-07-23 01:59 UTCEG score recompute
  3. 2026-07-22 22:46 UTCEG score recompute
  4. 2026-07-22 14:06 UTCEPSS rescore
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  6. 2026-07-21 15:22 UTCEPSS rescore
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  12. 2026-07-18 13:29 UTCOSV refresh
  13. 2026-07-18 10:02 UTCEPSS rescore
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  24. 2026-07-11 08:25 UTCEPSS rescore
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  1. 2026-07-09 19:07 UTCEPSS rescore
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  11. 2026-07-02 16:57 UTCEPSS rescore
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  13. 2026-06-30 23:20 UTCEPSS rescore
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  15. 2026-06-30 17:00 UTCOSV refresh
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  20. 2026-06-27 03:06 UTCEPSS rescore
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  22. 2026-06-25 13:48 UTCEPSS rescore
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  24. 2026-06-24 14:03 UTCEPSS rescore
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  26. 2026-06-23 21:31 UTCEPSS rescore
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  28. 2026-06-22 14:24 UTCEPSS rescore
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  30. 2026-06-21 14:55 UTCEPSS rescore
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  34. 2026-06-19 19:24 UTCEPSS rescore
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  36. 2026-06-18 17:51 UTCEPSS rescore
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  39. 2026-06-16 17:51 UTCEPSS rescore
  40. 2026-06-15 17:46 UTCEPSS rescore
  41. 2026-06-14 23:15 UTCEPSS rescore
  42. 2026-06-13 22:58 UTCEPSS rescore
  43. 2026-06-13 22:58 UTCEPSS rescore
  44. 2026-06-12 23:37 UTCOSV refresh
  45. 2026-06-12 23:10 UTCEPSS rescore
  46. 2026-06-11 13:58 UTCEPSS rescore
  47. 2026-06-10 22:16 UTCEPSS rescore
  48. 2026-06-10 13:20 UTCEPSS rescore
  49. 2026-06-08 14:15 UTCEPSS rescore
  50. 2026-06-07 15:23 UTCEPSS rescore
  51. 2026-06-07 15:23 UTCEPSS rescore
  52. 2026-06-06 13:46 UTCEPSS rescore
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  55. 2026-06-05 22:45 UTCEPSS rescore
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  64. 2026-06-01 13:50 UTCEPSS rescore
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  66. 2026-05-31 22:29 UTCEPSS rescore
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  68. 2026-05-31 00:15 UTCEPSS rescore
  69. 2026-05-29 13:42 UTCEPSS rescore
  70. 2026-05-28 13:43 UTCEPSS rescore
  71. 2026-05-28 13:43 UTCEPSS rescore
  72. 2026-05-27 13:39 UTCEPSS rescore
  73. 2026-05-27 13:39 UTCEPSS rescore
  74. 2026-05-26 11:21 UTCEG score recompute
  75. 2026-05-26 11:21 UTCGHSA enrichment

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Frequently asked(5)

What is CVE-2021-28697?
CVE-2021-28697 is a high vulnerability published on August 27, 2021. grant table v2 status pages may remain accessible after de-allocation Guest get permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, get de-allocated when a guest…
When was CVE-2021-28697 disclosed?
CVE-2021-28697 was first published in the National Vulnerability Database on August 27, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-28697 actively exploited?
CVE-2021-28697 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 17.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-28697?
CVE-2021-28697 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2021-28697?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-28697, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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