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%CVSS: 5.5Exploit: None knownExposed: 0

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

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
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
28%
KEV
Not listed

Published

February 17, 2021

Last Modified

November 21, 2024

References (14)

Affected Packages

(6 across 5 ecosystems)
Debian:9(2)
PackageVulnerable rangeFixed inDependents
linux4.9.107-1 ... 4.9.88-1~bpo8+1 (65 versions)4.9.258-1—
linux-4.194.19.132-1~deb9u1 ... 4.19.171-2~deb9u1 (6 versions)4.19.181-1~deb9u1—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.19-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.19-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.19-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.19-1—

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 9× in last 7d / 35× 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 136 total refreshes for this CVE.

  1. 2026-08-20 22:52 UTCEPSS rescore
  2. 2026-08-20 08:31 UTCOSV refresh
  3. 2026-08-19 17:01 UTCEPSS rescore
  4. 2026-08-18 13:45 UTCEPSS rescore
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  18. 2026-08-05 03:40 UTCOSV refresh
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  1. 2026-07-30 01:28 UTCEPSS rescore
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  8. 2026-07-23 14:16 UTCEPSS rescore
  9. 2026-07-23 01:59 UTCEG score recompute
  10. 2026-07-22 22:45 UTCEG score recompute
  11. 2026-07-22 14:06 UTCEPSS rescore
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  15. 2026-07-20 17:05 UTCEPSS rescore
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  17. 2026-07-19 02:27 UTCEPSS rescore
  18. 2026-07-19 02:27 UTCEPSS rescore
  19. 2026-07-19 01:59 UTCOSV refresh
  20. 2026-07-18 10:02 UTCEPSS rescore
  21. 2026-07-18 10:02 UTCEPSS rescore
  22. 2026-07-16 17:00 UTCEPSS rescore
  23. 2026-07-15 16:55 UTCEPSS rescore
  24. 2026-07-15 16:55 UTCEPSS rescore
  25. 2026-07-15 01:58 UTCEPSS rescore
  26. 2026-07-13 22:27 UTCEPSS rescore
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  28. 2026-07-13 06:10 UTCEPSS rescore
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  31. 2026-07-11 08:25 UTCEPSS rescore
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  40. 2026-07-05 02:28 UTCEPSS rescore
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  43. 2026-07-02 16:57 UTCEPSS rescore
  44. 2026-07-01 15:03 UTCEPSS rescore
  45. 2026-07-01 08:48 UTCOSV refresh
  46. 2026-06-30 23:20 UTCEPSS rescore
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  48. 2026-06-29 14:04 UTCEPSS rescore
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  74. 2026-06-13 22:58 UTCEPSS rescore
  75. 2026-06-13 22:58 UTCEPSS rescore

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 in the National Vulnerability Database 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% probability of exploitation in the next 30 days, which ranks it in the top 72.2% of all 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?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-26932, 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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