CVE-2020-7776: Phpoffice/phpspreadsheet Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-4mqv-gcr3-pff9
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CVSS 6.4
CWE-79
Published
Advisory Summary

CVE-2020-7776 is a MODERATE (CVSS 6.4) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Phpoffice/phpspreadsheet libraries in the Packagist ecosystem. The issue involves cross-site scripting in phpoffice/phpspreadsheet. Remediation is available by upgrading affected packages to version 1.16.0.

CVE-2020-7776 at a Glance

CVE Identifier CVE-2020-7776
GHSA Identifier GHSA-4mqv-gcr3-pff9
Severity MODERATE
CVSS v3.1 Base Score 6.4
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Phpoffice/phpspreadsheet
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 6.4

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:C/C:L/I:L/A:N).

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

How to Fix CVE-2020-7776

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

phpoffice/phpspreadsheet fixed: 1.16.0 
Upgrade phpoffice/phpspreadsheet to 1.16.0
phpoffice/phpexcel fixed: Latest secure release 
Upgrade phpoffice/phpexcel to Latest secure release
Verify Direct and Transitive Dependencies

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

inspect dependencies for phpoffice/phpspreadsheet

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-7776, inspect your project dependencies for Phpoffice/phpspreadsheet:

inspect dependencies for phpoffice/phpspreadsheet

Analyze the terminal output to locate any version of Phpoffice/phpspreadsheet in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.16.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Phpoffice/phpspreadsheet, 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

This affects the package phpoffice/phpspreadsheet. The library is vulnerable to XSS when creating an html output from an excel file by adding a comment on any cell. The root cause of this issue is within the HTML writer where user comments are concatenated as part of link and this is returned as HTML.

CVE-2020-7776 Affected Phpoffice/phpspreadsheet Versions

2 component(s)
Fixed Versions:
1.16.0
Product / Package Ecosystem Affected Versions Fixed Version
phpoffice/phpspreadsheet
 Packagist
< 1.16.0
1.16.0
phpoffice/phpexcel
 Packagist
≤ 1.8.2

References

NVD — CVE-2020-7776 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-7776
Phpoffice/phpspreadsheet Source Repository REPOSITORY
https://github.com/PHPOffice/PhpSpreadsheet/pull/1719
Security Fix Commit FIX COMMIT
https://github.com/PHPOffice/PhpSpreadsheet/commit/0ed5b800be2136bcb8fa9c1bdf59abc957a98845
Phpoffice/phpspreadsheet Source Repository REPOSITORY
https://github.com/FriendsOfPHP/security-advisories/blob/master/phpoffice/phpspreadsheet/CVE-2020-7776.yaml
Phpoffice/phpspreadsheet Source Repository REPOSITORY
https://github.com/PHPOffice/PhpSpreadsheet/blob/master/src/PhpSpreadsheet/Writer/Html.php%23L1792
snyk.io/vuln/snyk-php-phpof... WEB
https://snyk.io/vuln/SNYK-PHP-PHPOFFICEPHPSPREADSHEET-1048856

Frequently Asked Questions

What is CVE-2020-7776?
CVE-2020-7776 is a security vulnerability in Phpoffice/phpspreadsheet involving Cross-site scripting in phpoffice/phpspreadsheet under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Phpoffice/phpspreadsheet versions are affected?
Affected versions include releases prior to 1.16.0 across affected packages: phpoffice/phpspreadsheet, phpoffice/phpexcel.
What version fixes CVE-2020-7776?
Upgrading to 1.16.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is phpoffice/phpspreadsheet affected?
Yes, phpoffice/phpspreadsheet is affected in releases prior to 1.16.0. Upgrade your dependency to 1.16.0 or later.
Is phpoffice/phpexcel affected?
Yes, phpoffice/phpexcel is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2020-7776?
CVE-2020-7776 has a CVSS v3.1 base score of 6.4 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2020-7776?
CVE-2020-7776 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Packagist dependencies for CVE-2020-7776?
Run the dependency tree command: 'inspect dependencies for phpoffice/phpspreadsheet'. 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-4mqv-gcr3-pff9",
  "modified" : "2025-03-06T18:08:48Z",
  "published" : "2021-05-06T18:53:37Z",
  "aliases" : [ "CVE-2020-7776" ],
  "summary" : "Cross-site scripting in phpoffice/phpspreadsheet",
  "details" : "This affects the package phpoffice/phpspreadsheet. The library is vulnerable to XSS when creating an html output from an excel file by adding a comment on any cell. The root cause of this issue is within the HTML writer where user comments are concatenated as part of link and this is returned as HTML.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "phpoffice/phpspreadsheet"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.16.0"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "phpoffice/phpexcel"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.8.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-7776"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/PHPOffice/PhpSpreadsheet/pull/1719"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/PHPOffice/PhpSpreadsheet/commit/0ed5b800be2136bcb8fa9c1bdf59abc957a98845"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/phpoffice/phpspreadsheet/CVE-2020-7776.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/PHPOffice/PhpSpreadsheet/blob/master/src/PhpSpreadsheet/Writer/Html.php%23L1792"
  }, {
    "type" : "WEB",
    "url" : "https://snyk.io/vuln/SNYK-PHP-PHPOFFICEPHPSPREADSHEET-1048856"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-04-09T21:12:55Z",
    "nvd_published_at" : "2020-12-09T17:15:00Z"
  }
}