CVE-2020-10571: Psd tools Potential Buffer Overflow Vulnerability

CRITICAL
Advisory Identifier: GHSA-22jr-vc7j-g762
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CVSS 9.8
CWE-754
Published
Advisory Summary

CVE-2020-10571 is a CRITICAL (CVSS 9.8) potential buffer overflow vulnerability (CWE-754: Improper Check for Unusual or Exceptional Conditions) affecting Psd tools libraries in the PyPI ecosystem. The issue involves potential buffer overflow in psd-tools. Remediation is available by upgrading affected packages to version 1.9.4.

CVE-2020-10571 at a Glance

CVE Identifier CVE-2020-10571
GHSA Identifier GHSA-22jr-vc7j-g762
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-754: Improper Check for Unusual or Exceptional Conditions
Affected Product Psd tools
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-2020-10571

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

psd-tools fixed: 1.9.4 
pip install psd-tools>=1.9.4
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 psd-tools

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2020-10571, inspect your installed packages using pip:

pip show psd-tools

Analyze the terminal output to locate any version of Psd tools in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.9.4), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-754: Improper Check for Unusual or Exceptional Conditions, where the product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product. In Psd tools, 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

### Impact An issue was discovered in psd-tools before 1.9.4. The Cython implementation of RLE decoding did not check for malformed PSD input data during decoding to the PIL.Image or NumPy format, leading to a Buffer Overflow. ### Patches Users of psd-tools version v1.8.37 to v1.9.3 should upgrade to v1.9.4. ### Workarounds Without Cython present on installation, buffer overflow does not occur but IndexError will be thrown. However, already installed psd-tools with Cython extention should be upgraded. ### References https://github.com/psd-tools/psd-tools/pull/198 ### For more information If you have any questions or comments about this advisory: * Open an issue in [psd-tools](https://github.com/psd-tools/psd-tools/issues)

CVE-2020-10571 Affected Psd tools Versions

1 component(s)
Fixed Versions:
1.9.4
Product / Package Ecosystem Affected Versions Fixed Version
psd-tools
pypi/psd-tools
PyPI
≥ 1.8.37
< 1.9.4
1.9.4

References

GitHub Advisory / Wiki ADVISORY
https://github.com/psd-tools/psd-tools/security/advisories/GHSA-22jr-vc7j-g762
NVD — CVE-2020-10571 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-10571
Psd tools Source Repository REPOSITORY
https://github.com/psd-tools/psd-tools/pull/198
Security Fix Commit FIX COMMIT
https://github.com/psd-tools/psd-tools/commit/fd51f8b4a52bc9c1c06d1035dfdf2cd920e87074
Psd tools Source Repository REPOSITORY
https://github.com/psd-tools/psd-tools
Psd tools Release RELEASE
https://github.com/psd-tools/psd-tools/releases/tag/v1.9.4
Psd tools Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/psd-tools/PYSEC-2020-91.yaml

Frequently Asked Questions

What is CVE-2020-10571?
CVE-2020-10571 is a security vulnerability in Psd tools involving Potential buffer overflow in psd-tools under CWE-754: Improper Check for Unusual or Exceptional Conditions.
Which Psd tools versions are affected?
Affected versions include releases prior to 1.9.4 across affected packages: psd-tools.
What version fixes CVE-2020-10571?
Upgrading to 1.9.4 (or the latest patched release for your respective branch) resolves the vulnerability.
Is psd-tools affected?
Yes, psd-tools is affected in releases prior to 1.9.4. Upgrade your dependency to 1.9.4 or later.
What is the CVSS score of CVE-2020-10571?
CVE-2020-10571 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-2020-10571?
CVE-2020-10571 is classified under CWE-754: Improper Check for Unusual or Exceptional Conditions (The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.).
How can I check PyPI dependencies for CVE-2020-10571?
Run the dependency tree command: 'pip show psd-tools'. 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-22jr-vc7j-g762",
  "modified" : "2026-09-24T14:55:09Z",
  "published" : "2020-03-16T22:46:19Z",
  "aliases" : [ "CVE-2020-10571" ],
  "summary" : "Potential buffer overflow in psd-tools",
  "details" : "### Impact\nAn issue was discovered in psd-tools before 1.9.4. The Cython implementation of RLE decoding did not check for malformed PSD input data during decoding to the PIL.Image or NumPy format, leading to a Buffer Overflow.\n\n### Patches\nUsers of psd-tools version v1.8.37 to v1.9.3 should upgrade to v1.9.4.\n\n### Workarounds\nWithout Cython present on installation, buffer overflow does not occur but IndexError will be thrown. However, already installed psd-tools with Cython extention should be upgraded.\n\n### References\nhttps://github.com/psd-tools/psd-tools/pull/198\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [psd-tools](https://github.com/psd-tools/psd-tools/issues)",
  "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" : "psd-tools"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.8.37"
      }, {
        "fixed" : "1.9.4"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.9.3"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/psd-tools/psd-tools/security/advisories/GHSA-22jr-vc7j-g762"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-10571"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/psd-tools/psd-tools/pull/198"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/psd-tools/psd-tools/commit/fd51f8b4a52bc9c1c06d1035dfdf2cd920e87074"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/psd-tools/psd-tools"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/psd-tools/psd-tools/releases/tag/v1.9.4"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/psd-tools/PYSEC-2020-91.yaml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-754" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-03-16T20:55:37Z",
    "nvd_published_at" : null
  }
}