What is CVE-2018-17983?

CVE-2018-17983 is a critical-severity vulnerability in Mercurial, classified under Out-of-bounds Read. CVSS score: 9.1/10. Published 2018-10-04.

How severe is CVE-2018-17983?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Out-of-bounds Read in Mercurial

CVE-2018-17983

cext/manifest.c in Mercurial before 4.7.2 has an out-of-bounds read during parsing of a malformed manifest entry.

Vulnerability class: Buffer Overflow

Published 2018-10-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.

EPSS exploit prediction

EPSS: 0.020 (80.5th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 80th percentile — 80.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.020 · newest: 0.020 · change: 0.000

Affected products

Mercurial

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

www.mercurial-scm.org/repo/hg/rev/5405cb1a7901 (Patch)
www.mercurial-scm.org/wiki/WhatsNew (Release Notes)

Frequently asked questions

What is CVE-2018-17983?: CVE-2018-17983 is a critical-severity vulnerability in Mercurial, classified under Out-of-bounds Read. CVSS score: 9.1/10. Published 2018-10-04.
How severe is CVE-2018-17983?: Critical severity. CVSS v3 base score is 9.1 out of 10.