CVE-2026-28364

HIGHNVD 7.87.9
EchelonGraph scoreMEDIUM confidence

“▲” beside the score: it is higher than NVD's CVSS score.

Score 7.9 from GitHub Security Advisory (severity: HIGH) published 2026-02-27. NVD baseline CVSS 7.8; sources differ by 0.1.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this week
7.9EG
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: 0.3%CVSS: 7.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

In OCaml before 4.14.3 and 5.x before 5.4.1, a buffer over-read in Marshal deserialization (runtime/intern.c) enables remote code execution through a multi-phase attack chain. The vulnerability stems from missing bounds validation in the readblock() function, which performs unbounded memcpy() operations using attacker-controlled lengths from crafted Marshal data.

CVSS v3
7.8
EG Score
7.9HIGHmedium confidence
EG Risk
36
EG Risk 36/100

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 (value × EchelonGraph’s weight)
Severity79% × 45%
The EG Score, 7.9 of 10.
Exploitation0.3% × 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
0.3%
EPSS %ILE
23rd
KEV
Not listed

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.

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

February 27, 2026

Last Modified

July 15, 2026

Advisory Details (5)

Auto-updated Jul 1, 2026
Patch available. Sources: redhat.
Red Hat

Affected: Red Hat Enterprise Linux 10",

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28364.json
Red Hat

2443348 – (CVE-2026-28364) CVE-2026-28364 ocaml: OCaml: Remote code execution via buffer over-read in Marshal deserialization

https://bugzilla.redhat.com/show_bug.cgi?id=2443348
Red HatMentions a patch (unverified)

cve-details

https://access.redhat.com/security/cve/CVE-2026-28364
Web page

OSV - Open Source Vulnerabilities

https://osv.dev/vulnerability/OSEC-2026-01
Web page

security-advisories/2026/OSEC-2026-01.json at generated-osv · ocaml/security-advisories · GitHub

https://github.com/ocaml/security-advisories/blob/generated-osv/2026/OSEC-2026-01.json

Vendor Advisories for CVE-2026-28364(2)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
ocaml4.11.1-4 ... 5.5.0-1~exp2 (37 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
ocaml4.13.1-4 ... 5.5.1-1~exp1 (33 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
ocaml5.3.0-3 ... 5.5.1-1~exp1 (12 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
ocaml5.3.0-3 ... 5.4.1-1~exp1 (8 versions)
  • every version up to 5.4.1-1: fixed in 5.4.1-1
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 26× 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 95 of 146 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. 5 repeat rows among the latest 100 are merged into the row they repeat. The 51 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-11 19:59 UTCEG score recompute
  2. 2026-10-11 17:12 UTCEG score recompute
  3. 2026-10-11 14:42 UTCEG score recompute
  4. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  5. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  6. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  7. 2026-10-09 05:58 UTCOSV refresh
  8. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  9. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  10. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  11. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  12. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  13. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  14. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  15. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  16. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  17. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  18. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  19. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  20. 2026-09-19 13:02 UTCOSV refresh
  21. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  22. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  23. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  24. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  25. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 11th percentile
Show 70 more
  1. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  2. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  3. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  4. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  5. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  6. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  7. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  8. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  9. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  10. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  11. 2026-08-31 16:34 UTCOSV refresh
  12. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  13. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  14. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  15. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  16. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  17. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  18. 2026-08-24 14:17 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  19. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  20. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  21. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  22. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  23. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  24. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  25. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  26. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  27. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  28. 2026-08-14 21:08 UTCVendor advisory
  29. 2026-08-14 21:08 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  30. 2026-08-14 08:50 UTCEG score recompute
  31. 2026-08-14 08:50 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  32. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  33. 2026-08-13 00:48 UTCEG score recompute
  34. 2026-08-13 00:48 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  35. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  36. 2026-08-11 23:36 UTCEG score recompute
  37. 2026-08-11 23:36 UTCVendor advisory
  38. 2026-08-11 23:36 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  39. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  40. 2026-08-11 06:10 UTCEG score recompute
  41. 2026-08-11 06:10 UTCVendor advisory
  42. 2026-08-11 06:10 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  43. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  44. 2026-08-10 08:30 UTCVendor advisory
  45. 2026-08-10 08:30 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  46. 2026-08-09 19:59 UTCEG score recompute
  47. 2026-08-09 19:59 UTCVendor advisory
  48. 2026-08-09 19:59 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  49. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  50. 2026-08-09 08:29 UTCEG score recompute
  51. 2026-08-09 08:29 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  52. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  53. 2026-08-08 07:59 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  54. 2026-08-07 20:29 UTCEG score recompute
  55. 2026-08-07 20:29 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  56. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  57. 2026-08-06 02:55 UTCEG score recompute
  58. 2026-08-06 02:55 UTCVendor advisory
  59. 2026-08-06 02:55 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  60. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  61. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  62. 2026-08-04 04:54 UTCEG score recompute
  63. 2026-08-04 04:54 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  64. 2026-08-03 10:36 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  65. 2026-08-02 19:23 UTCEG score recompute
  66. 2026-08-02 19:23 UTCVendor advisory
  67. 2026-08-02 19:23 UTCGHSA enrichmentGHSA-g54x-7hpm-29q8 · GitHub severity HIGH · GitHub CVSS 7.9
  68. 2026-08-02 02:26 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  69. 2026-08-01 04:16 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  70. 2026-07-30 16:27 UTCEPSS rescoreEPSS 0.2% · 11th percentile

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Frequently asked(5)

What is CVE-2026-28364?
CVE-2026-28364 is a high-severity vulnerability; its CVE record was published on February 27, 2026. In OCaml before 4.14.3 and 5.x before 5.4.1, a buffer over-read in Marshal deserialization (runtime/intern.c) enables remote code execution through a multi-phase attack chain. The vulnerability stems from missing bounds validation in the readblock() function, which performs unbounded memcpy()…
When was the CVE record for CVE-2026-28364 published?
The CVE record for CVE-2026-28364 was published on February 27, 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 July 15, 2026; the record at its source may have been updated since.
Is CVE-2026-28364 actively exploited?
CVE-2026-28364 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (23rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-28364?
CVE-2026-28364 has a CVSS v3 base score of 7.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 7.9 (HIGH).
How do I remediate CVE-2026-28364?
A fix for CVE-2026-28364 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-28364 are linked in the Vendor Advisories panel on this page.

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