OSEC-2026-22

See a problem?
Import Source
https://github.com/ocaml/security-advisories/blob/generated-osv/2026/OSEC-2026-22.json
JSON Data
https://api.test.osv.dev/v1/vulns/OSEC-2026-22
Published
2026-10-23T21:30:00Z
Modified
2026-10-23T22:15:03Z
Severity
  • 5.5 (Medium) CVSS_V4 - CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:P CVSS Calculator
Summary
Integer overflow in Unix.map_file
Details

ANT-2026-6W9NPC2Q mmap dimension product integer overflow

Fix

Use caml_umul_overflow instead of * when multiplying bigarray dimensions, which detects integer overflows and raise Failure. Negative positions are also rejected by raising Invalid_argument.

Am I affected?

If either the dimensions or the file size in a call to Unix.map_file from your code is user controllable then you are potentially affected.

Score notes

The vulnerability is in a library, and the CVSS score is calculated under worst case assumptions. For an actual application the score will depend on how much an attacker can control the input to this function (if at all).

Timeline

  • 2026-08-24: vulnerability was found
  • 2026-08-27: forwarded report to security@ocaml.org
  • 2026-09-29: fix merged to trunk
Database specific 
{
    "cwe": [
        "CWE-190"
    ],
    "human_link": "https://github.com/ocaml/security-advisories/tree/main/advisories/2026/OSEC-2026-22.md",
    "osv": "https://github.com/ocaml/security-advisories/tree/generated-osv/2026/OSEC-2026-22.json"
}
Credits
    • Anthropic - REPORTER
    • Hannes Mehnert - COORDINATOR
    • Edwin Török - COORDINATOR
    • Nicolás Ojeda Bär - REMEDIATION_REVIEWER
    • Edwin Török - REMEDIATION_REVIEWER
    • Xavier Leroy - REMEDIATION_DEVELOPER

Affected packages

opam / ocaml

Package

Name
ocaml
Purl
pkg:opam/ocaml

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
5.5.2
Type
GIT
Repo
https://github.com/ocaml/ocaml
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
de57bb4f59c3302260aaeaaa4dfee12695597d25
Type
GIT
Repo
https://github.com/ocaml/ocaml
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
ff978d2139ba638886c2565f2d86c0ee265840a5

Affected versions

3.*
3.07
3.07+1
3.07+2
3.08.0
3.08.1
3.08.2
3.08.3
3.08.4
3.09.0
3.09.1
3.09.2
3.09.3
3.10.0
3.10.1
3.10.2
3.11.0
3.11.1
3.11.2
3.12.0
3.12.1
4.*
4.00.0
4.00.1
4.01.0
4.02.0
4.02.1
4.02.2
4.02.3
4.02.4
4.03.0
4.03.1
4.04.0
4.04.1
4.04.2
4.04.3
4.05.0
4.05.1
4.06.0
4.06.1
4.06.2
4.07.0
4.07.1
4.07.2
4.08.0
4.08.1
4.08.2
4.09.0
4.09.1
4.09.2
4.10.0
4.10.1
4.10.2
4.10.3
4.11.0
4.11.1
4.11.2
4.11.3
4.12.0
4.12.1
4.12.2
4.13.0
4.13.1
4.13.2
4.14.0
4.14.1
4.14.2
4.14.3
4.14.4
4.14.5
5.*
5.0.0
5.0.1
5.1.0
5.1.1
5.1.2
5.2.0
5.2.1
5.2.2
5.3.0
5.3.1
5.4.0
5.4.1
5.4.2
5.5.0
5.5.0-alpha1
5.5.0-alpha2
5.5.0-alpha3
5.5.0-beta1
5.5.0-rc1
5.5.1
Other
flambda_fork_point

Ecosystem specific 

{
    "affected_bindings": [
        "Unix.map_file"
    ],
    "opam_constraint": "ocaml {< \"5.5.2\"}"
}

Database specific

source 
"https://github.com/ocaml/security-advisories/blob/generated-osv/2026/OSEC-2026-22.json"