CVE-2020-5312: Pillow PCX P Mode Buffer Overflow Vulnerability

CRITICAL
Advisory Identifier: GHSA-p49h-hjvm-jg3h
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CVSS 9.8
CWE-120
Published
Advisory Summary

CVE-2020-5312 is a CRITICAL (CVSS 9.8) pcx p mode buffer overflow vulnerability (CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')) affecting Pillow libraries in the PyPI ecosystem. The issue involves pcx p mode buffer overflow in pillow. Remediation is available by upgrading affected packages to version 6.2.2.

CVE-2020-5312 at a Glance

CVE Identifier CVE-2020-5312
GHSA Identifier GHSA-p49h-hjvm-jg3h
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Affected Product Pillow
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-2020-5312

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

pillow fixed: 6.2.2 
pip install pillow>=6.2.2
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 pillow

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2020-5312, inspect your installed packages using pip:

pip show pillow

Analyze the terminal output to locate any version of Pillow in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 6.2.2), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow'), where the product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer. In Pillow, 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

libImaging/PcxDecode.c in Pillow before 6.2.2 has a PCX P mode buffer overflow.

CVE-2020-5312 Affected Pillow Versions

1 component(s)
Fixed Versions:
6.2.2
Product / Package Ecosystem Affected Versions Fixed Version
pillow
pypi/pillow
PyPI
< 6.2.2
6.2.2

References

NVD — CVE-2020-5312 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-5312
Security Fix Commit FIX COMMIT
https://github.com/python-pillow/Pillow/commit/93b22b846e0269ee9594ff71a72bec02d2bea8fd
Pillow Security Information SECURITY
https://www.debian.org/security/2020/dsa-4631
usn.ubuntu.com/4272-1 WEB
https://usn.ubuntu.com/4272-1
Pillow Release RELEASE
https://pillow.readthedocs.io/en/stable/releasenotes/6.2.2.html
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3DUMIBUYGJRAVJCTFUWBRLVQKOUTVX5P
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2MMU3WT2X64GS5WHDPKKC2WZA7UIIQ3A
Pillow Source Repository REPOSITORY
https://github.com/python-pillow/Pillow
Pillow Source Repository REPOSITORY
https://github.com/pypa/advisory-db/blob/7872b0a91b4d980f749e6d75a81f8cc1af32829f/vulns/pillow/PYSEC-2020-83.yaml
Pillow Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/pillow/PYSEC-2020-83.yaml
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-p49h-hjvm-jg3h
access.redhat.com/errata/rhsa-2020:06... WEB
https://access.redhat.com/errata/RHSA-2020:0694
access.redhat.com/errata/rhsa-2020:06... WEB
https://access.redhat.com/errata/RHSA-2020:0683
access.redhat.com/errata/rhsa-2020:06... WEB
https://access.redhat.com/errata/RHSA-2020:0681
access.redhat.com/errata/rhsa-2020:05... WEB
https://access.redhat.com/errata/RHSA-2020:0580
access.redhat.com/errata/rhsa-2020:05... WEB
https://access.redhat.com/errata/RHSA-2020:0578
access.redhat.com/errata/rhsa-2020:05... WEB
https://access.redhat.com/errata/RHSA-2020:0566

Frequently Asked Questions

What is CVE-2020-5312?
CVE-2020-5312 is a security vulnerability in Pillow involving PCX P mode buffer overflow in Pillow under CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow').
Which Pillow versions are affected?
Affected versions include releases prior to 6.2.2 across affected packages: pillow.
What version fixes CVE-2020-5312?
Upgrading to 6.2.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is pillow affected?
Yes, pillow is affected in releases prior to 6.2.2. Upgrade your dependency to 6.2.2 or later.
What is the CVSS score of CVE-2020-5312?
CVE-2020-5312 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-2020-5312?
CVE-2020-5312 is classified under CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') (The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.).
How can I check PyPI dependencies for CVE-2020-5312?
Run the dependency tree command: 'pip show pillow'. 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-p49h-hjvm-jg3h",
  "modified" : "2024-10-08T13:03:01Z",
  "published" : "2021-11-03T18:05:04Z",
  "aliases" : [ "CVE-2020-5312" ],
  "summary" : "PCX P mode buffer overflow in Pillow",
  "details" : "libImaging/PcxDecode.c in Pillow before 6.2.2 has a PCX P mode buffer overflow.",
  "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" : "pillow"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "6.2.2"
      } ]
    } ]
  } ],
  "references" : [ {
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  }, {
    "type" : "WEB",
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  }, {
    "type" : "WEB",
    "url" : "https://www.debian.org/security/2020/dsa-4631"
  }, {
    "type" : "WEB",
    "url" : "https://usn.ubuntu.com/4272-1"
  }, {
    "type" : "WEB",
    "url" : "https://pillow.readthedocs.io/en/stable/releasenotes/6.2.2.html"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3DUMIBUYGJRAVJCTFUWBRLVQKOUTVX5P"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2MMU3WT2X64GS5WHDPKKC2WZA7UIIQ3A"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/python-pillow/Pillow"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-db/blob/7872b0a91b4d980f749e6d75a81f8cc1af32829f/vulns/pillow/PYSEC-2020-83.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/pillow/PYSEC-2020-83.yaml"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-p49h-hjvm-jg3h"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0694"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0683"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0681"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0580"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0578"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2020:0566"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-120" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-11-03T17:28:10Z",
    "nvd_published_at" : "2020-01-03T01:15:00Z"
  }
}