CVE-2021-26932

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2022-05-24. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

An issue was discovered in the Linux kernel 3.2 through 5.10.16, as used by Xen. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one is reported to the backend driver, and the backend driver then loops over the results, performing follow-up actions based on the success or failure of each operation. Unfortunately, when running in PV mode, the Linux backend drivers mishandle this: Some errors are ignored, effectively implying their success from the success of related batch elements. In other cases, errors resulting from one batch element lead to further batch elements not being inspected, and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and drivers/xen/gntdev.c.

CVSS v3
5.5
EG Score
5.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100CISA SSVC

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
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.3%
EPSS %ILE
25th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

February 17, 2021

Last Modified

November 21, 2024

References (14)

Vendor Advisories for CVE-2021-26932(1)

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

Affected Packages

(6 across 5 ecosystems)
Debian:9(2)
PackageVulnerable rangeFix by version rangeDependents
linux4.9.107-1 ... 4.9.88-1~bpo8+1 (65 versions)
  • every version up to 4.9.258-1: fixed in 4.9.258-1
—
linux-4.194.19.132-1~deb9u1 ... 4.19.171-2~deb9u1 (6 versions)
  • every version up to 4.19.181-1~deb9u1: fixed in 4.19.181-1~deb9u1
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.10.19-1: fixed in 5.10.19-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.10.19-1: fixed in 5.10.19-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.10.19-1: fixed in 5.10.19-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.10.19-1: fixed in 5.10.19-1
—

Data Freshness Timeline

(refreshed 9× in last 7d / 32× 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 186 total refreshes for this CVE.

  1. 2026-10-06 15:14 UTCEPSS rescore
  2. 2026-10-05 17:40 UTCEPSS rescore
  3. 2026-10-04 23:19 UTCEPSS rescore
  4. 2026-10-03 14:22 UTCEPSS rescore
  5. 2026-10-03 14:22 UTCEPSS rescore
  6. 2026-10-02 16:22 UTCEPSS rescore
  7. 2026-10-01 19:46 UTCEPSS rescore
  8. 2026-09-30 15:33 UTCEG score recompute
  9. 2026-09-30 15:00 UTCEPSS rescore
  10. 2026-09-29 15:15 UTCEPSS rescore
  11. 2026-09-28 13:47 UTCEPSS rescore
  12. 2026-09-27 13:41 UTCEPSS rescore
  13. 2026-09-26 15:54 UTCEPSS rescore
  14. 2026-09-26 15:54 UTCEPSS rescore
  15. 2026-09-26 09:25 UTCOSV refresh
  16. 2026-09-26 00:21 UTCEPSS rescore
  17. 2026-09-24 14:00 UTCEPSS rescore
  18. 2026-09-23 13:44 UTCEPSS rescore
  19. 2026-09-21 20:28 UTCEPSS rescore
  20. 2026-09-19 15:37 UTCEPSS rescore
  21. 2026-09-18 19:23 UTCEPSS rescore
  22. 2026-09-17 19:23 UTCEPSS rescore
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  24. 2026-09-16 14:05 UTCEPSS rescore
  25. 2026-09-15 03:06 UTCEPSS rescore
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  1. 2026-09-15 03:06 UTCEPSS rescore
  2. 2026-09-13 16:43 UTCEPSS rescore
  3. 2026-09-12 14:57 UTCEPSS rescore
  4. 2026-09-11 14:49 UTCEPSS rescore
  5. 2026-09-11 09:33 UTCEPSS rescore
  6. 2026-09-08 21:56 UTCEPSS rescore
  7. 2026-09-07 15:58 UTCEPSS rescore
  8. 2026-09-06 22:13 UTCOSV refresh
  9. 2026-09-06 13:44 UTCEPSS rescore
  10. 2026-09-05 15:25 UTCEPSS rescore
  11. 2026-09-04 13:57 UTCEPSS rescore
  12. 2026-09-04 05:03 UTCEPSS rescore
  13. 2026-09-04 05:03 UTCEPSS rescore
  14. 2026-09-02 14:08 UTCEPSS rescore
  15. 2026-09-01 13:50 UTCEPSS rescore
  16. 2026-09-01 03:32 UTCEPSS rescore
  17. 2026-08-30 19:14 UTCEPSS rescore
  18. 2026-08-30 01:19 UTCEPSS rescore
  19. 2026-08-28 21:37 UTCEPSS rescore
  20. 2026-08-27 14:22 UTCEPSS rescore
  21. 2026-08-26 14:42 UTCEPSS rescore
  22. 2026-08-25 13:45 UTCEPSS rescore
  23. 2026-08-24 14:12 UTCEPSS rescore
  24. 2026-08-23 00:16 UTCEPSS rescore
  25. 2026-08-21 23:46 UTCEPSS rescore
  26. 2026-08-20 22:52 UTCEPSS rescore
  27. 2026-08-20 08:31 UTCOSV refresh
  28. 2026-08-19 17:01 UTCEPSS rescore
  29. 2026-08-18 13:45 UTCEPSS rescore
  30. 2026-08-17 13:44 UTCEPSS rescore
  31. 2026-08-16 14:53 UTCEPSS rescore
  32. 2026-08-16 02:11 UTCEPSS rescore
  33. 2026-08-16 02:11 UTCEPSS rescore
  34. 2026-08-15 01:27 UTCEPSS rescore
  35. 2026-08-13 21:57 UTCEPSS rescore
  36. 2026-08-12 13:47 UTCEPSS rescore
  37. 2026-08-11 13:38 UTCEPSS rescore
  38. 2026-08-09 13:43 UTCEPSS rescore
  39. 2026-08-08 16:33 UTCEPSS rescore
  40. 2026-08-07 16:23 UTCEPSS rescore
  41. 2026-08-06 13:43 UTCEPSS rescore
  42. 2026-08-05 19:14 UTCEPSS rescore
  43. 2026-08-05 03:40 UTCOSV refresh
  44. 2026-08-04 15:06 UTCEPSS rescore
  45. 2026-08-04 10:34 UTCEPSS rescore
  46. 2026-08-03 10:33 UTCEPSS rescore
  47. 2026-08-02 02:24 UTCEPSS rescore
  48. 2026-08-01 04:13 UTCEPSS rescore
  49. 2026-07-30 16:25 UTCEPSS rescore
  50. 2026-07-30 16:25 UTCEPSS rescore
  51. 2026-07-30 01:28 UTCEPSS rescore
  52. 2026-07-30 01:27 UTCEPSS rescore
  53. 2026-07-28 15:33 UTCEPSS rescore
  54. 2026-07-26 14:52 UTCEPSS rescore
  55. 2026-07-26 14:52 UTCEPSS rescore
  56. 2026-07-25 14:15 UTCEPSS rescore
  57. 2026-07-24 14:15 UTCEPSS rescore
  58. 2026-07-23 14:16 UTCEPSS rescore
  59. 2026-07-23 01:59 UTCEG score recompute
  60. 2026-07-22 22:45 UTCEG score recompute
  61. 2026-07-22 14:06 UTCEPSS rescore
  62. 2026-07-22 14:06 UTCEPSS rescore
  63. 2026-07-21 15:22 UTCEPSS rescore
  64. 2026-07-21 15:22 UTCEPSS rescore
  65. 2026-07-20 17:05 UTCEPSS rescore
  66. 2026-07-19 14:28 UTCEPSS rescore
  67. 2026-07-19 02:27 UTCEPSS rescore
  68. 2026-07-19 02:27 UTCEPSS rescore
  69. 2026-07-19 01:59 UTCOSV refresh
  70. 2026-07-18 10:02 UTCEPSS rescore
  71. 2026-07-18 10:02 UTCEPSS rescore
  72. 2026-07-16 17:00 UTCEPSS rescore
  73. 2026-07-15 16:55 UTCEPSS rescore
  74. 2026-07-15 16:55 UTCEPSS rescore
  75. 2026-07-15 01:58 UTCEPSS rescore

Related CVEs(same product)

Frequently asked(5)

What is CVE-2021-26932?
CVE-2021-26932 is a medium vulnerability published on February 17, 2021. An issue was discovered in the Linux kernel 3.2 through 5.10.16, as used by Xen. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one is reported to the backend driver, and the backend driver then…
When was CVE-2021-26932 disclosed?
CVE-2021-26932 was first published on February 17, 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-2021-26932 actively exploited?
CVE-2021-26932 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (25th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-26932?
CVE-2021-26932 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2021-26932?
A fix for CVE-2021-26932 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-26932 are linked in the Vendor Advisories panel on this page.

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