CVE-2015-0838: Dulwich Dulwich Buffer Overflow When Handling Vulnerability

CRITICAL
Advisory Identifier: GHSA-vjjf-3rvg-gv3v
Share
CVSS 9.8
CWE-119
Published
Advisory Summary

CVE-2015-0838 is a CRITICAL (CVSS 9.8) dulwich buffer overflow when handling vulnerability (CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer) affecting Dulwich libraries in the PyPI ecosystem. The issue involves dulwich buffer overflow when handling pack files. Remediation is available by upgrading affected packages to version 0.9.9.

CVE-2015-0838 at a Glance

CVE Identifier CVE-2015-0838
GHSA Identifier GHSA-vjjf-3rvg-gv3v
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
Affected Product Dulwich
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 9.8

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

How to Fix CVE-2015-0838

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

dulwich fixed: 0.9.9 
pip install dulwich>=0.9.9
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 dulwich

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2015-0838, inspect your installed packages using pip:

pip show dulwich

Analyze the terminal output to locate any version of Dulwich in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.9.9), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer, where the product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. this may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data. In Dulwich, 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

Buffer overflow in the C implementation of the `apply_delta` function `in _pack.c` in Dulwich before 0.9.9 allows remote attackers to execute arbitrary code via a crafted pack file.

CVE-2015-0838 Affected Dulwich Versions

1 component(s)
Fixed Versions:
0.9.9
Product / Package Ecosystem Affected Versions Fixed Version
dulwich
pypi/dulwich
PyPI
< 0.9.9
0.9.9

References

NVD — CVE-2015-0838 NVD
https://nvd.nist.gov/vuln/detail/CVE-2015-0838
Dulwich Source Repository REPOSITORY
https://github.com/jelmer/dulwich
Dulwich Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/dulwich/PYSEC-2015-35.yaml
lists.launchpad.net/dulwich-users/msg00... WEB
https://lists.launchpad.net/dulwich-users/msg00829.html
Dulwich Security Information SECURITY
http://www.debian.org/security/2015/dsa-3206

Frequently Asked Questions

What is CVE-2015-0838?
CVE-2015-0838 is a security vulnerability in Dulwich involving Dulwich Buffer Overflow when handling pack files under CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer.
Which Dulwich versions are affected?
Affected versions include releases prior to 0.9.9 across affected packages: dulwich.
What version fixes CVE-2015-0838?
Upgrading to 0.9.9 (or the latest patched release for your respective branch) resolves the vulnerability.
Is dulwich affected?
Yes, dulwich is affected in releases prior to 0.9.9. Upgrade your dependency to 0.9.9 or later.
What is the CVSS score of CVE-2015-0838?
CVE-2015-0838 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2015-0838?
CVE-2015-0838 is classified under CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer (The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.).
How can I check PyPI dependencies for CVE-2015-0838?
Run the dependency tree command: 'pip show dulwich'. 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-vjjf-3rvg-gv3v",
  "modified" : "2025-04-14T21:57:56Z",
  "published" : "2022-05-17T04:14:09Z",
  "aliases" : [ "CVE-2015-0838" ],
  "summary" : "Dulwich Buffer Overflow when handling pack files",
  "details" : "Buffer overflow in the C implementation of the `apply_delta` function `in _pack.c` in Dulwich before 0.9.9 allows remote attackers to execute arbitrary code via a crafted pack file.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "dulwich"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.9.9"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2015-0838"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jelmer/dulwich"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/dulwich/PYSEC-2015-35.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://lists.launchpad.net/dulwich-users/msg00829.html"
  }, {
    "type" : "WEB",
    "url" : "http://www.debian.org/security/2015/dsa-3206"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-119" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-04-22T22:58:51Z",
    "nvd_published_at" : "2015-03-31T14:59:00Z"
  }
}