CVE-2021-34693

MEDIUMNVD 5.55.5
EchelonGraph scoreMEDIUM confidence

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

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, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2021-21343 (ENISA EUVD) · GHSA-c44h-4g88-mw48 (GitHub Security Advisories)Source: ENISA EUVD

5.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 5.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

net/can/bcm.c in the Linux kernel through 5.12.10 allows local users to obtain sensitive information from kernel stack memory because parts of a data structure are uninitialized.

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.
Exploitation0.5% × 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: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.5%
EPSS %ILE
40th
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.GitHub Security Advisory CVSS
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-25). 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.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.

A fix is available. Apply it within your standard update timelines.

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.

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

June 14, 2021

Last Modified

October 8, 2026

Advisory Details (7)

Auto-updated Oct 9, 2026
Patch available.
Web pageMentions a patch (unverified)

[SECURITY] [DLA 2713-1] linux security update

https://lists.debian.org/debian-lts-announce/2021/07/msg00014.html
Web page

can: bcm: fix infoleak in struct bcm_msg_head - kernel/git/torvalds/linux.git - Linux kernel source tree

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=5e87ddbe3942e27e939bdc02deb8579b0cbd8ecc
Web page

oss-security - CVE-2021-34693: Infoleak in CAN BCM protocol in Linux kernel

http://www.openwall.com/lists/oss-security/2021/06/15/1
Web page

[SECURITY] [DSA 4941-1] linux security update

https://www.debian.org/security/2021/dsa-4941
Web pageMentions a patch (unverified)

[SECURITY] [DLA 2713-2] linux security update

https://lists.debian.org/debian-lts-announce/2021/07/msg00016.html
Web pageMentions a patch (unverified)

[SECURITY] [DLA 2714-1] linux-4.19 security update

https://lists.debian.org/debian-lts-announce/2021/07/msg00015.html

Vendor Advisories for CVE-2021-34693(1)

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

Patch Availability(7)

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.

Affected Packages

(7 across 6 ecosystems)
Debian:9(2)
PackageVulnerable rangeFix by version rangeDependents
linux4.9.107-1 ... 4.9.88-1~bpo8+1 (67 versions)
  • every version up to 4.9.272-2: fixed in 4.9.272-2
—
linux-4.194.19.132-1~deb9u1 ... 4.19.194-1~deb9u1 (8 versions)
  • every version up to 4.19.194-3~deb9u1: fixed in 4.19.194-3~deb9u1
—
Debian:10(1)
PackageVulnerable rangeFix by version rangeDependents
linux4.19.118-1 ... 4.19.98-1~bpo9+1 (34 versions)
  • every version up to 4.19.194-3: fixed in 4.19.194-3
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.10.46-1: fixed in 5.10.46-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.10.46-1: fixed in 5.10.46-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.10.46-1: fixed in 5.10.46-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.10.46-1: fixed in 5.10.46-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(7)

Data Freshness Timeline

(refreshed 7× in last 7d / 40× 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.

Showing the most recent 94 of 217 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 6 repeat rows among the latest 100 are merged into the row they repeat. The 123 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:29 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  2. 2026-10-31 16:28 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  3. 2026-10-30 16:30 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  4. 2026-10-29 16:29 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  5. 2026-10-28 16:28 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  6. 2026-10-27 16:28 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  7. 2026-10-26 16:28 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  8. 2026-10-25 18:26 UTCEG score recompute
  9. 2026-10-25 16:28 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  10. 2026-10-24 23:12 UTCEG score recompute
  11. 2026-10-24 23:12 UTCVendor advisory
  12. 2026-10-24 23:12 UTCGHSA enrichmentGHSA-c44h-4g88-mw48 · GitHub CVSS 5.5
  13. 2026-10-24 16:28 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  14. 2026-10-23 16:28 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  15. 2026-10-22 16:29 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  16. 2026-10-21 16:28 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  17. 2026-10-20 16:28 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  18. 2026-10-19 16:28 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  19. 2026-10-18 16:28 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  20. 2026-10-18 08:59 UTCEG score recompute
  21. 2026-10-17 16:29 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  22. 2026-10-16 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  23. 2026-10-15 16:28 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  24. 2026-10-14 16:28 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  25. 2026-10-13 16:28 UTCEPSS rescoreEPSS 0.5% · 39th percentile
Show 69 more
  1. 2026-10-12 19:15 UTCEG score recompute
  2. 2026-10-12 16:29 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  3. 2026-10-11 23:40 UTCEG score recompute
  4. 2026-10-11 13:43 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  5. 2026-10-10 19:56 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  6. 2026-10-09 20:04 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  7. 2026-10-08 21:23 UTCEG score recompute
  8. 2026-10-08 21:23 UTCVendor advisory
  9. 2026-10-08 21:23 UTCGHSA enrichmentGHSA-c44h-4g88-mw48 · GitHub CVSS 5.5
  10. 2026-10-08 16:39 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  11. 2026-10-07 23:44 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  12. 2026-10-06 15:14 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  13. 2026-10-05 17:40 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  14. 2026-10-04 23:19 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  15. 2026-10-03 14:22 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  16. 2026-10-01 19:46 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  17. 2026-09-30 15:37 UTCEG score recompute
  18. 2026-09-30 15:00 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  19. 2026-09-29 15:15 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  20. 2026-09-28 13:47 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  21. 2026-09-27 13:41 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  22. 2026-09-26 15:54 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  23. 2026-09-26 00:21 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  24. 2026-09-26 00:12 UTCOSV refresh
  25. 2026-09-24 14:00 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  26. 2026-09-23 13:44 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  27. 2026-09-22 14:44 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  28. 2026-09-21 20:28 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  29. 2026-09-20 20:12 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  30. 2026-09-19 15:38 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  31. 2026-09-18 19:23 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  32. 2026-09-17 19:23 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  33. 2026-09-16 14:05 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  34. 2026-09-15 03:06 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  35. 2026-09-13 16:43 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  36. 2026-09-12 14:57 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  37. 2026-09-11 14:49 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  38. 2026-09-11 09:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  39. 2026-09-08 21:56 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  40. 2026-09-07 15:58 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  41. 2026-09-06 15:01 UTCOSV refresh
  42. 2026-09-06 13:45 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  43. 2026-09-05 15:25 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  44. 2026-09-04 13:57 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  45. 2026-09-04 05:03 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  46. 2026-09-02 14:08 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  47. 2026-09-01 13:50 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  48. 2026-09-01 03:32 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  49. 2026-08-30 19:14 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  50. 2026-08-30 01:19 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  51. 2026-08-28 21:37 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  52. 2026-08-27 14:22 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  53. 2026-08-26 14:42 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  54. 2026-08-25 13:46 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  55. 2026-08-24 14:13 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  56. 2026-08-23 00:16 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  57. 2026-08-21 23:46 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  58. 2026-08-20 22:52 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  59. 2026-08-20 01:04 UTCOSV refresh
  60. 2026-08-19 17:01 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  61. 2026-08-18 13:45 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  62. 2026-08-17 13:44 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  63. 2026-08-16 14:53 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  64. 2026-08-16 02:11 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  65. 2026-08-15 01:27 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  66. 2026-08-13 21:57 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  67. 2026-08-12 13:48 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  68. 2026-08-11 13:38 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  69. 2026-08-09 13:44 UTCEPSS rescoreEPSS 0.5% · 38th percentile

Frequently asked(5)

What is CVE-2021-34693?
CVE-2021-34693 is a medium-severity vulnerability; its CVE record was published on June 14, 2021. net/can/bcm.c in the Linux kernel through 5.12.10 allows local users to obtain sensitive information from kernel stack memory because parts of a data structure are uninitialized.
When was the CVE record for CVE-2021-34693 published?
The CVE record for CVE-2021-34693 was published on June 14, 2021. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 8, 2026; the record at its source may have been updated since.
Is CVE-2021-34693 actively exploited?
CVE-2021-34693 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (40th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-34693?
CVE-2021-34693 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2021-34693?
A fix for CVE-2021-34693 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-34693 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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