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NVD / CVE Program· CNA mitre

CVE-2026-28364: 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…

Noroxi assessment

Priority: Monitor (action score 31/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.24% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: OCaml OCaml 4.14.3, 5.4.1; azl3 ocaml 5.1.1-1 on Azure Linux 3.0 5.1.1-2; cbl2 ocaml 4.13.1-2 on CBL Mariner 2.0 4.13.1-3.

Low priority for now. Upgrade to OCaml OCaml 4.14.3, 5.4.1; azl3 ocaml 5.1.1-1 on Azure Linux 3.0 5.1.1-2; cbl2 ocaml 4.13.1-2 on CBL Mariner 2.0 4.13.1-3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.8 · v3.1—Proof of concept Fix available
Published
Feb 27, 2026
Updated
Jul 15, 2026
EPSS
0.2% · 15th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.8
CNA · mitre
7.9
0.1 point gap

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-28364

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
ocamlocaml

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • ocaml ocamlbefore 4.14.3
  • ocaml ocaml5.0.0 and later · before 5.4.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (mitre). Independent of NVD's CPE analysis and usually ahead of it.

  • OCaml OCaml

    • before 4.14.3affected · semver
    • 5.0.0 and later · before 5.4.1affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12ocamlfrom 0—
Debian:14ocamlbefore 5.4.1-15.4.1-1
openSUSE:Leap 15.6ocamlbefore 4.14.2-150600.3.3.14.14.2-150600.3.3.1
openSUSE:Leap 16.0ocamlbefore 4.14.2-160000.4.14.14.2-160000.4.1
openSUSE:Tumbleweedocamlbefore 4.14.4-1.14.14.4-1.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSocamlbefore 4.05.0-150200.15.3.14.05.0-150200.15.3.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7ocamlbefore 4.14.2-150600.3.3.14.14.2-150600.3.3.1

Same product

ocaml: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-9838The caml_ba_deserialize function in byterun/bigarray.c in the standard library in OCaml 4.06.0 has an integer overflow which, in situations…
    40Plan
  • CVE-2017-9772Insufficient sanitisation in the OCaml compiler versions 4.04.0 and 4.04.1 allows external code to be executed with raised privilege in…
    40Plan
  • CVE-2015-8869OCaml before 4.03.0 does not properly handle sign extensions, which allows remote attackers to conduct buffer overflow attacks or obtain…
    38Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2017-9779Sep 7, 2017 · OCaml compiler allows attackers to have unspecified impact via unknown vectors, a similar issue to CVE-2017-9772 "but with much less impact.
    31Monitor
  • Later →CVE-2026-34353Mar 27, 2026 · In OCaml through 4.14.3, Bigarray.reshape allows an integer overflow, and resultant reading of arbitrary memory, when untrusted data is…
    20Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
OCaml OCaml4.14.3Vendor (CNA)
OCaml OCaml5.4.1Vendor (CNA)
azl3 ocaml 5.1.1-1 on Azure Linux 3.05.1.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 ocaml 4.13.1-2 on CBL Mariner 2.04.13.1-3 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:ocaml5.4.1-1 · Debian:14Package registry (OSV)
opensuse:ocaml4.14.2-150600.3.3.1 · openSUSE:Leap 15.6Package registry (OSV)
suse:ocaml4.05.0-150200.15.3.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:ocaml4.14.2-150600.3.3.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:02026-09-24

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+209 d
  3. TodayNov 11, 2026+258 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-126 · Buffer Over-read

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Exploit maturitynone → poc
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records