The caml_ba_deserialize function in byterun/bigarray.c in the standard library in OCaml 4.06.0 has an integer overflow which, in situations where marshalled data is accepted from an untrusted source, allows remote attackers to cause a denial of service (memory corruption) or possibly execute arbitrary code via a crafted object.
Conclusion & alert: CVE-2018-9838 is rated High Risk (67.8/100): CVSS Critical severity, with high exploitation likelihood (EPSS 8.12%, 92th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-04-13 | 11.73% | 8.12% | -3.62% |
| 2 | 2026-03-25 | 3.59% | 11.73% | +8.14% |
| 3 | 2025-12-03 | — | 3.59% | — |
Full EPSS history (17 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.0 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2018-9838 not yet assigned priority: Debian including 1 source packages (ocaml), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2018-9838 |
gentoo
|
normal | CVE-2018-9838: 1 GLSA(s) (202007-48), 1 atom(s) (dev-lang/ocaml); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2018-9838 |
redhat
|
low | — | https://access.redhat.com/security/cve/CVE-2018-9838 |
suse
|
high | CVE-2018-9838 severity important: SUSE including 35 source package names (ocaml, ocaml-4.02.1-4.6.1, …), 107 product×package rows across 26 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (26 product lines)): Fixed 62, Known Not Affected 45. | https://www.suse.com/security/cve/CVE-2018-9838/ |
ubuntu
|
low | CVE-2018-9838 low priority: Ubuntu including 1 source packages (ocaml), 15 status rows across 15 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, trusty, upstream, xenial): not-affected 8, released 4, ignored 3. | https://ubuntu.com/security/CVE-2018-9838 |
| URL | Tags |
|---|---|
| https://caml.inria.fr/mantis/view.php?id=7765 | Issue Tracking Vendor Advisory |
| https://security.gentoo.org/glsa/202007-48 |