CVE-2021-29155

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
Trending — 3 sources updated this weekElevated
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 5.5Exploit: NoneExposed: 0

A fix is available — apply it.

An issue was discovered in the Linux kernel through 5.11.x. kernel/bpf/verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory. Specifically, for sequences of pointer arithmetic operations, the pointer modification performed by the first operation is not correctly accounted for when restricting subsequent operations.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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%
Exploitation40% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
61.3%
KEV
Not listed

Published

April 20, 2021

Last Modified

November 21, 2024

References (28)

Vendor Advisories for CVE-2021-29155(2)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatkernel-rt-0:4.18.0-348.rt7.130.el82021-11-09redhat
redhatkernel-0:4.18.0-348.el82021-11-09redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 14× in last 7d / 51× 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 103 total refreshes for this CVE.

  1. 2026-07-23 01:59 UTCEG score recompute
  2. 2026-07-22 22:46 UTCEG score recompute
  3. 2026-07-22 14:06 UTCEPSS rescore
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  11. 2026-07-18 21:59 UTCOSV refresh
  12. 2026-07-18 10:02 UTCEPSS rescore
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  14. 2026-07-16 17:00 UTCEPSS rescore
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  1. 2026-07-08 15:12 UTCEPSS rescore
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  10. 2026-07-02 16:57 UTCEPSS rescore
  11. 2026-07-01 15:03 UTCEPSS rescore
  12. 2026-07-01 04:48 UTCOSV refresh
  13. 2026-06-30 23:20 UTCEPSS rescore
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  25. 2026-06-23 21:31 UTCEPSS rescore
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  27. 2026-06-22 14:24 UTCEPSS rescore
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  29. 2026-06-21 14:55 UTCEPSS rescore
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  31. 2026-06-21 01:58 UTCEPSS rescore
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  40. 2026-06-14 23:15 UTCEPSS rescore
  41. 2026-06-13 22:58 UTCEPSS rescore
  42. 2026-06-13 22:58 UTCEPSS rescore
  43. 2026-06-13 08:43 UTCOSV refresh
  44. 2026-06-12 23:10 UTCEPSS rescore
  45. 2026-06-11 13:58 UTCEPSS rescore
  46. 2026-06-10 22:16 UTCEPSS rescore
  47. 2026-06-10 13:20 UTCEPSS rescore
  48. 2026-06-08 14:15 UTCEPSS rescore
  49. 2026-06-07 15:23 UTCEPSS rescore
  50. 2026-06-07 15:23 UTCEPSS rescore
  51. 2026-06-06 13:46 UTCEPSS rescore
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  54. 2026-06-05 22:45 UTCEPSS rescore
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  56. 2026-06-05 06:09 UTCEPSS rescore
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  58. 2026-06-04 13:10 UTCEPSS rescore
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  60. 2026-06-02 20:11 UTCEPSS rescore
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  63. 2026-06-01 13:50 UTCEPSS rescore
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  65. 2026-05-31 22:29 UTCEPSS rescore
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  67. 2026-05-31 00:15 UTCEPSS rescore
  68. 2026-05-29 13:42 UTCEPSS rescore
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  70. 2026-05-28 13:43 UTCEPSS rescore
  71. 2026-05-27 13:39 UTCEPSS rescore
  72. 2026-05-27 13:39 UTCEPSS rescore
  73. 2026-05-26 18:07 UTCEG score recompute
  74. 2026-05-26 18:07 UTCVendor advisory
  75. 2026-05-26 18:06 UTCGHSA enrichment

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCbenschlueter/CVE-2021-29155
    First seen Jun 3, 2021

    Proof of Concept CVE-2021-29155

    Open source ↗

Frequently asked(5)

What is CVE-2021-29155?
CVE-2021-29155 is a medium vulnerability published on April 20, 2021. An issue was discovered in the Linux kernel through 5.11.x. kernel/bpf/verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory. Specifically, for sequences of…
When was CVE-2021-29155 disclosed?
CVE-2021-29155 was first published in the National Vulnerability Database on April 20, 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-2021-29155 actively exploited?
CVE-2021-29155 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 61.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-29155?
CVE-2021-29155 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2021-29155?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-29155, 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.

Dependency Blast Radius

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