CVE-2023-3640

HIGHNVD 7.87.8
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 7.8 under NVD CVSS v3. EPSS exploit probability: 0.8% (54th percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 7.0 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2023-07-24) is not newer than that change (2026-07-21), so it does not.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this weekElevated
7.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • Public exploit or proof-of-concept code is available
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 7.8Exploit: Public PoCExposed services: Not assessed

A fix is available — apply it.

A possible unauthorized memory access flaw was found in the Linux kernel's cpu_entry_area mapping of X86 CPU data to memory, where a user may guess the location of exception stacks or other important data. Based on the previous CVE-2023-0597, the 'Randomize per-cpu entry area' feature was implemented in /arch/x86/mm/cpu_entry_area.c, which works through the init_cea_offsets() function when KASLR is enabled. However, despite this feature, there is still a risk of per-cpu entry area leaks. This issue could allow a local user to gain access to some important data with memory in an expected location and potentially escalate their privileges on the system.

CVSS v3
7.8
EG Score
7.8HIGHmedium confidence
EG Risk
51
EG Risk 51/100

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.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
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
0.8%
EPSS %ILE
54th
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.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.8% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-20). 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 24, 2023

Last Modified

July 21, 2026

Advisory Details (3)

Auto-updated Jun 26, 2026
Patch available. Sources: redhat.
Red HatMentions a patch (unverified)

2217523 – (CVE-2023-3640) CVE-2023-3640 Kernel: x86/mm: a per-cpu entry area leak was identified through the init_cea_offsets function when prefetchnta and prefetcht2 instructions being used for the per-cpu entry area mapping to the user space

https://bugzilla.redhat.com/show_bug.cgi?id=2217523
Red HatMentions a patch (unverified)

cve-details

https://access.redhat.com/security/cve/CVE-2023-3640
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2023:6583

Vendor Advisories for CVE-2023-3640(2)

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

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatkernel-0:5.14.0-362.8.1.el9_32023-11-07redhat

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
linux5.10.103-1 ... 7.2~rc5-1~exp1 (499 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 7.2~rc7-1~exp1 (353 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (176 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (176 versions)
  • every version on: no fix on record
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 35× 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 85 of 205 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. 15 repeat rows among the latest 100 are merged into the row they repeat. The 120 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-23 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  2. 2026-10-22 16:31 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  3. 2026-10-21 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  4. 2026-10-21 01:23 UTCEG score recompute
  5. 2026-10-21 01:22 UTCGHSA enrichmentGHSA-g854-mv2r-2r5h · GitHub severity HIGH · GitHub CVSS 7.0
  6. 2026-10-20 16:30 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  7. 2026-10-19 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  8. 2026-10-18 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  9. 2026-10-18 07:57 UTCEG score recompute
  10. 2026-10-17 16:30 UTCEPSS rescoreEPSS 0.8% · 54th percentile
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  12. 2026-10-15 16:29 UTCEPSS rescoreEPSS 0.8% · 54th percentile
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  14. 2026-10-13 16:30 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  15. 2026-10-13 09:24 UTCOSV refresh
  16. 2026-10-12 18:23 UTCEG score recompute
  17. 2026-10-12 16:31 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  18. 2026-10-11 21:50 UTCEG score recompute
  19. 2026-10-11 13:45 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  20. 2026-10-10 19:57 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  21. 2026-10-09 20:05 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
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  24. 2026-10-06 15:15 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  25. 2026-10-05 17:41 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
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  1. 2026-10-03 14:23 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  2. 2026-10-01 19:48 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  3. 2026-09-30 16:26 UTCEG score recompute
  4. 2026-09-30 15:01 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  5. 2026-09-29 15:17 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  6. 2026-09-28 13:49 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
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  8. 2026-09-26 15:56 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  9. 2026-09-26 00:22 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  10. 2026-09-24 14:01 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  11. 2026-09-23 13:46 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  12. 2026-09-23 04:02 UTCOSV refresh
  13. 2026-09-20 20:14 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  14. 2026-09-18 19:25 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  15. 2026-09-17 19:25 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  16. 2026-09-16 14:06 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
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  18. 2026-09-13 16:44 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  19. 2026-09-12 14:58 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
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  21. 2026-09-11 09:34 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  22. 2026-09-08 21:58 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  23. 2026-09-07 15:59 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  24. 2026-09-06 13:45 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
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  26. 2026-09-04 13:58 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  27. 2026-09-04 05:04 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  28. 2026-09-03 22:59 UTCOSV refresh
  29. 2026-09-02 14:09 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  30. 2026-09-01 13:51 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  31. 2026-08-30 19:15 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
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  37. 2026-08-23 00:17 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  38. 2026-08-21 23:47 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  39. 2026-08-20 22:53 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  40. 2026-08-19 17:02 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  41. 2026-08-18 13:46 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  42. 2026-08-17 13:45 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  43. 2026-08-17 12:16 UTCOSV refresh
  44. 2026-08-16 14:54 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  45. 2026-08-16 02:12 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  46. 2026-08-15 01:28 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  47. 2026-08-13 21:58 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  48. 2026-08-12 13:48 UTCEPSS rescoreEPSS 0.8% · 52nd percentile
  49. 2026-08-11 13:39 UTCEPSS rescoreEPSS 0.8% · 51st percentile
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  57. 2026-08-02 06:45 UTCOSV refresh
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  60. 2026-07-30 16:26 UTCEPSS rescoreEPSS 0.8% · 51st percentile

Publicly available exploits

(1 reference)

Public exploit code is referenced for this CVE (1 GitHub PoC). Defenders should treat patch urgency accordingly.

  • GitHub PoCpray77/CVE-2023-3640
    Published Jun 20, 2023

    SCTF 2023 kernel pwn && CVE-2023-3640

    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2023-3640?
CVE-2023-3640 is a high-severity vulnerability; its CVE record was published on July 24, 2023. A possible unauthorized memory access flaw was found in the Linux kernel's cpuentryarea mapping of X86 CPU data to memory, where a user may guess the location of exception stacks or other important data. Based on the previous CVE-2023-0597, the 'Randomize per-cpu entry area' feature was implemented…
When was CVE-2023-3640 made public?
CVE-2023-3640 was made public on June 23, 2023: that is the date its CVE record's CNA, Red Hat, Inc., gives for when the vulnerability was made public. The CVE record itself was published on July 24, 2023. EchelonGraph's copy of the record carries a last-modified date of July 21, 2026; the record at its source may have been updated since.
Is CVE-2023-3640 actively exploited?
CVE-2023-3640 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (54th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2023-3640?
CVE-2023-3640 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2023-3640?
A fix for CVE-2023-3640 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2023-3640 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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