CVE-2017-9462: Mercurial Remote Code Execution Vulnerability

HIGH
Advisory Identifier: GHSA-ghjx-3jg5-h6r2
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CVSS 8.8
CWE-732
Published
Advisory Summary

CVE-2017-9462 is a HIGH (CVSS 8.8) remote code execution vulnerability (CWE-732: Incorrect Permission Assignment for Critical Resource) affecting Mercurial libraries in the PyPI ecosystem. The issue involves mercurial has incorrect permission assignment for critical resource. Remediation is available by upgrading affected packages to version 4.1.3.

CVE-2017-9462 at a Glance

CVE Identifier CVE-2017-9462
GHSA Identifier GHSA-ghjx-3jg5-h6r2
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-732: Incorrect Permission Assignment for Critical Resource
Affected Product Mercurial
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

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

How to Fix CVE-2017-9462

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: 4.1.3 
pip install mercurial>=4.1.3
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-2017-9462, 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 4.1.3), 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-732: Incorrect Permission Assignment for Critical Resource, where the product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors. 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

In Mercurial before 4.1.3, "hg serve --stdio" allows remote authenticated users to launch the Python debugger, and consequently execute arbitrary code, by using --debugger as a repository name.

CVE-2017-9462 Affected Mercurial Versions

1 component(s)
Fixed Versions:
4.1.3
Product / Package Ecosystem Affected Versions Fixed Version
mercurial
pypi/mercurial
PyPI
< 4.1.3
4.1.3

References

NVD — CVE-2017-9462 NVD
https://nvd.nist.gov/vuln/detail/CVE-2017-9462
access.redhat.com/errata/rhsa-2017:15... WEB
https://access.redhat.com/errata/RHSA-2017:1576
bugs.debian.org/861243 WEB
https://bugs.debian.org/861243
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-ghjx-3jg5-h6r2
Mercurial Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/mercurial/PYSEC-2017-91.yaml
lists.debian.org/debian-lts-announce... WEB
https://lists.debian.org/debian-lts-announce/2018/07/msg00005.html
Mercurial Security Information SECURITY
https://security.gentoo.org/glsa/201709-18
Mercurial Security Information SECURITY
https://web.archive.org/web/20200227162318/http://www.securityfocus.com/bid/99123
Mercurial Security Information SECURITY
https://www.mercurial-scm.org/repo/hg/rev/77eaf9539499
Mercurial Security Information SECURITY
https://www.mercurial-scm.org/wiki/WhatsNew#Mercurial_4.1.3_.282017-4-18.29
Mercurial Security Information SECURITY
http://www.debian.org/security/2017/dsa-3963

Frequently Asked Questions

What is CVE-2017-9462?
CVE-2017-9462 is a security vulnerability in Mercurial involving Mercurial has Incorrect Permission Assignment for Critical Resource under CWE-732: Incorrect Permission Assignment for Critical Resource.
Which Mercurial versions are affected?
Affected versions include releases prior to 4.1.3 across affected packages: mercurial.
What version fixes CVE-2017-9462?
Upgrading to 4.1.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mercurial affected?
Yes, mercurial is affected in releases prior to 4.1.3. Upgrade your dependency to 4.1.3 or later.
What is the CVSS score of CVE-2017-9462?
CVE-2017-9462 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2017-9462?
CVE-2017-9462 is classified under CWE-732: Incorrect Permission Assignment for Critical Resource (The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.).
How can I check PyPI dependencies for CVE-2017-9462?
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-ghjx-3jg5-h6r2",
  "modified" : "2024-10-01T19:23:42Z",
  "published" : "2018-07-13T15:17:10Z",
  "aliases" : [ "CVE-2017-9462" ],
  "summary" : "Mercurial has Incorrect Permission Assignment for Critical Resource",
  "details" : "In Mercurial before 4.1.3, \"hg serve --stdio\" allows remote authenticated users to launch the Python debugger, and consequently execute arbitrary code, by using --debugger as a repository name.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "mercurial"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.1.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2017-9462"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2017:1576"
  }, {
    "type" : "WEB",
    "url" : "https://bugs.debian.org/861243"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-ghjx-3jg5-h6r2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/mercurial/PYSEC-2017-91.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2018/07/msg00005.html"
  }, {
    "type" : "WEB",
    "url" : "https://security.gentoo.org/glsa/201709-18"
  }, {
    "type" : "WEB",
    "url" : "https://web.archive.org/web/20200227162318/http://www.securityfocus.com/bid/99123"
  }, {
    "type" : "WEB",
    "url" : "https://www.mercurial-scm.org/repo/hg/rev/77eaf9539499"
  }, {
    "type" : "WEB",
    "url" : "https://www.mercurial-scm.org/wiki/WhatsNew#Mercurial_4.1.3_.282017-4-18.29"
  }, {
    "type" : "WEB",
    "url" : "http://www.debian.org/security/2017/dsa-3963"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-732" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-06-16T21:37:26Z",
    "nvd_published_at" : null
  }
}