CVE-2026-64558

HIGHPre-NVD 7.87.8
EchelonGraph scoreMEDIUM confidence

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

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-07-29. A secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 4 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 7.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

s390/pkey: Check length in pkey_pckmo handler implementation

Explicitly check the length of the target buffer in the pkey_pckmo implementation of the key_to_protkey() handler function. The handler function fails, if the generated output data exceeds the length of the provided target buffer.

CVSS v3
7.8
EG Score
7.8HIGHmedium confidence
EG Risk
35
EG Risk 35/100

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)
Severity78% × 45%
Impact severity (EG Severity): CVSS 7.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 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 low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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
0.1%
EPSS %ILE
1st
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 (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.

EG Severity
7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-19). 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 low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

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

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (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

July 29, 2026

Last Modified

October 19, 2026

Advisory Details (4)

Auto-updated Jul 30, 2026
Patch available.
Web page

s390/pkey: Check length in pkey_pckmo handler implementation - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/614aa0491c7a190556c2345dddee0b6f5ed90989
Web page

s390/pkey: Check length in pkey_pckmo handler implementation - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/433e5e70cdc1edf382d28d08a885b22e2b98b7da
Web page

s390/pkey: Check length in pkey_pckmo handler implementation - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1ac287e2af9a9112fe271427ef45eceb26bce8b4
Web page

s390/pkey: Check length in pkey_pckmo handler implementation - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/02028a24e26d85262ab9c8fc4344e1f3503007fc

Vendor Advisories for CVE-2026-64558(2)

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

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux-6.12—
  • every version up to 6.12.100-1~deb12u1: fixed in 6.12.100-1~deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.38-1 ... 6.12.96-1 (31 versions)
  • every version up to 6.12.100-1: fixed in 6.12.100-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.1~rc7-1~exp1 (160 versions)
  • every version up to 7.1.5-1: fixed in 7.1.5-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(6)

Data Freshness Timeline

(refreshed 22× in last 7d / 75× 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 100 of 246 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. None are among the latest 100 rows. The 146 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-19 21:42 UTCEG score recompute
  2. 2026-10-19 21:42 UTCVendor advisory
  3. 2026-10-19 21:41 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  4. 2026-10-19 20:54 UTCEG score recompute
  5. 2026-10-19 20:54 UTCVendor advisory
  6. 2026-10-19 20:54 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  7. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  8. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  9. 2026-10-18 03:22 UTCEG score recompute
  10. 2026-10-16 17:36 UTCEG score recompute
  11. 2026-10-16 17:36 UTCVendor advisory
  12. 2026-10-16 17:35 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  13. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  14. 2026-10-16 16:09 UTCEG score recompute
  15. 2026-10-16 16:09 UTCVendor advisory
  16. 2026-10-16 16:09 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  17. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  18. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  19. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  20. 2026-10-13 11:39 UTCEG score recompute
  21. 2026-10-13 11:39 UTCVendor advisory
  22. 2026-10-13 11:39 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  23. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  24. 2026-10-12 15:47 UTCEG score recompute
  25. 2026-10-11 19:32 UTCEG score recompute
Show 75 more
  1. 2026-10-11 16:47 UTCEG score recompute
  2. 2026-10-11 14:09 UTCEG score recompute
  3. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  4. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  5. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  6. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  7. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  8. 2026-10-07 00:01 UTCEG score recompute
  9. 2026-10-07 00:01 UTCVendor advisory
  10. 2026-10-07 00:00 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  11. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  12. 2026-10-05 20:51 UTCEG score recompute
  13. 2026-10-05 20:51 UTCVendor advisory
  14. 2026-10-05 20:51 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  15. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  16. 2026-10-05 02:36 UTCEG score recompute
  17. 2026-10-05 02:36 UTCVendor advisory
  18. 2026-10-05 02:36 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  19. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  20. 2026-10-04 07:01 UTCEG score recompute
  21. 2026-10-04 07:01 UTCVendor advisory
  22. 2026-10-04 07:01 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  23. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  24. 2026-10-02 17:57 UTCEG score recompute
  25. 2026-10-02 17:57 UTCVendor advisory
  26. 2026-10-02 17:57 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  27. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  28. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  29. 2026-10-01 15:43 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  30. 2026-10-01 03:34 UTCEG score recompute
  31. 2026-10-01 03:34 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  32. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  33. 2026-09-29 07:35 UTCEG score recompute
  34. 2026-09-29 07:35 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  35. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  36. 2026-09-28 07:43 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  37. 2026-09-27 19:38 UTCEG score recompute
  38. 2026-09-27 19:37 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  39. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  40. 2026-09-25 05:38 UTCEG score recompute
  41. 2026-09-25 05:38 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  42. 2026-09-24 09:54 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  43. 2026-09-23 21:49 UTCEG score recompute
  44. 2026-09-23 21:49 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  45. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  46. 2026-09-23 03:54 UTCEG score recompute
  47. 2026-09-23 03:54 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  48. 2026-09-22 15:48 UTCEG score recompute
  49. 2026-09-22 15:48 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  50. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  51. 2026-09-20 00:23 UTCEG score recompute
  52. 2026-09-20 00:23 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  53. 2026-09-19 04:53 UTCEG score recompute
  54. 2026-09-19 04:53 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  55. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  56. 2026-09-18 15:17 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  57. 2026-09-18 01:40 UTCEG score recompute
  58. 2026-09-18 01:40 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  59. 2026-09-17 01:35 UTCEG score recompute
  60. 2026-09-17 01:35 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  61. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  62. 2026-09-16 05:48 UTCEG score recompute
  63. 2026-09-16 05:48 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  64. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  65. 2026-09-15 07:54 UTCEG score recompute
  66. 2026-09-15 07:54 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  67. 2026-09-14 09:01 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  68. 2026-09-13 20:55 UTCEG score recompute
  69. 2026-09-13 20:55 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  70. 2026-09-13 08:49 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  71. 2026-09-12 20:43 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  72. 2026-09-12 08:34 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  73. 2026-09-11 20:25 UTCEG score recompute
  74. 2026-09-11 20:25 UTCGHSA enrichmentGHSA-82p5-pf6r-jcxr · GitHub severity HIGH · GitHub CVSS 7.8
  75. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.1% · 2nd percentile

Frequently asked(5)

What is CVE-2026-64558?
CVE-2026-64558 is a high-severity vulnerability; its CVE record was published on July 29, 2026. In the Linux kernel, the following vulnerability has been resolved: s390/pkey: Check length in pkey_pckmo handler implementation Explicitly check the length of the target buffer in the pkey_pckmo implementation of the keytoprotkey() handler function. The handler function fails, if the generated…
When was the CVE record for CVE-2026-64558 published?
The CVE record for CVE-2026-64558 was published on July 29, 2026. 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 19, 2026; the record at its source may have been updated since.
Is CVE-2026-64558 actively exploited?
CVE-2026-64558 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-64558?
CVE-2026-64558 has a CVSS base score of 7.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-64558?
A fix for CVE-2026-64558 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-64558 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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