CVE-2019-3902

A flaw was found in Mercurial before 4.9. It was possible to use symlinks and subrepositories to defeat Mercurial's path-checking logic and write files outside a repository.

Published: 2019-04-22 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-3902 is rated Moderate Risk (43.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.53%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2019-3902

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 2026-03-23 0.55% 0.53% -0.02%
2 2026-02-28 0.75% 0.55% -0.20%
3 2026-02-05 — 0.75% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-3902

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.1 3.0 MEDIUM
CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 1.4 3.6 [email protected]
5.9 3.0 MEDIUM
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2019-3902

GitHub Security Advisory for CVE-2019-3902

GHSA-mq66-vcfc-8246 · Severity: medium · Ecosystem: pip — Mercurial Path Traversal/Link Following vulnerability

OS Trackers for CVE-2019-3902

vendor priority summary link
alpine medium CVE-2019-3902: 1 source package rows (mercurial); 10 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 10, open 0. https://security.alpinelinux.org/vuln/CVE-2019-3902
debian not yet assigned CVE-2019-3902 not yet assigned priority: Debian including 1 source packages (mercurial), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2019-3902
redhat medium — https://access.redhat.com/security/cve/CVE-2019-3902
suse medium CVE-2019-3902 severity moderate: SUSE including 15 source package names (mercurial-2.8.2-15.18.4, mercurial-4.5.2-3.9.44, …), 18 product×package rows across 13 product lines (SUSE Linux Enterprise Module for Basesystem 15 SP4, SUSE Linux Enterprise Module for Basesystem 15 SP5, … (13 product lines)): Fixed 18. https://www.suse.com/security/cve/CVE-2019-3902/
ubuntu medium CVE-2019-3902 medium priority: Ubuntu including 1 source packages (mercurial), 12 status rows across 12 suites (bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): not-affected 6, released 5, ignored 1. https://ubuntu.com/security/CVE-2019-3902

Affected software / configurations for CVE-2019-3902

Vendor Product Version Raw CPE
mercurial mercurial < 4.9 cpe:2.3:a:mercurial:mercurial:*:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*

References for CVE-2019-3902

cvelogic Threat Intelligence