CVE-2018-17983: Mercurial Mercurial Out-of-bounds Read Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-p575-cf9h-wv42
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CVSS 9.1
CWE-125
Published
Advisory Summary

CVE-2018-17983 is a HIGH (CVSS 9.1) mercurial out-of-bounds read vulnerability vulnerability (CWE-125: Out-of-bounds Read) affecting Mercurial libraries in the PyPI ecosystem. The issue involves mercurial out-of-bounds read vulnerability. Remediation is available by upgrading affected packages to version 4.7.2.

CVE-2018-17983 at a Glance

CVE Identifier CVE-2018-17983
GHSA Identifier GHSA-p575-cf9h-wv42
Severity HIGH
CVSS v3.1 Base Score 9.1
CWE Classification CWE-125: Out-of-bounds Read
Affected Product Mercurial
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2018-17983

To remediate this vulnerability, upgrade all affected Mercurial dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

mercurial fixed: 4.7.2 
pip install mercurial>=4.7.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show mercurial

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2018-17983, inspect your installed packages using pip:

pip show mercurial

Analyze the terminal output to locate any version of Mercurial in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.7.2), your application is affected.

Note: The pip show mercurial command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-125: Out-of-bounds Read, where the product reads data past the end, or before the beginning, of the intended buffer. In Mercurial, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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

CVE-2018-17983 Affected Mercurial Versions

1 component(s)
Fixed Versions:
4.7.2
Product / Package Ecosystem Affected Versions Fixed Version
mercurial
pypi/mercurial
PyPI
< 4.7.2
4.7.2

References

NVD — CVE-2018-17983 NVD
https://nvd.nist.gov/vuln/detail/CVE-2018-17983
Mercurial Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/mercurial/PYSEC-2018-91.yaml
Mercurial Security Information SECURITY
https://www.mercurial-scm.org/repo/hg/rev/5405cb1a7901
Mercurial Security Information SECURITY
https://www.mercurial-scm.org/wiki/WhatsNew#Mercurial_4.7.2_.282018-10-01.29

Frequently Asked Questions

What is CVE-2018-17983?
CVE-2018-17983 is a security vulnerability in Mercurial involving Mercurial Out-of-bounds Read vulnerability under CWE-125: Out-of-bounds Read.
Which Mercurial versions are affected?
Affected versions include releases prior to 4.7.2 across affected packages: mercurial.
What version fixes CVE-2018-17983?
Upgrading to 4.7.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mercurial affected?
Yes, mercurial is affected in releases prior to 4.7.2. Upgrade your dependency to 4.7.2 or later.
What is the CVSS score of CVE-2018-17983?
CVE-2018-17983 has a CVSS v3.1 base score of 9.1 (HIGH) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.
What CWE is associated with CVE-2018-17983?
CVE-2018-17983 is classified under CWE-125: Out-of-bounds Read (The product reads data past the end, or before the beginning, of the intended buffer.).
How can I check PyPI dependencies for CVE-2018-17983?
Run the dependency tree command: 'pip show mercurial'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-p575-cf9h-wv42",
  "modified" : "2024-09-24T20:45:43Z",
  "published" : "2022-05-14T01:49:39Z",
  "aliases" : [ "CVE-2018-17983" ],
  "summary" : "Mercurial Out-of-bounds Read vulnerability",
  "details" : "`cext/manifest.c` in Mercurial before 4.7.2 has an out-of-bounds read during parsing of a malformed manifest entry.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "mercurial"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.7.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2018-17983"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/mercurial/PYSEC-2018-91.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://www.mercurial-scm.org/repo/hg/rev/5405cb1a7901"
  }, {
    "type" : "WEB",
    "url" : "https://www.mercurial-scm.org/wiki/WhatsNew#Mercurial_4.7.2_.282018-10-01.29"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-125" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-05-01T16:55:10Z",
    "nvd_published_at" : "2018-10-04T23:29:00Z"
  }
}