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CVE-2020-7776· NVD / CVE Program· CNA snyk

Cross-site Scripting (XSS)

This affects the package phpoffice/phpspreadsheet from 0.0.0. 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. A fix for this issue is available on commit 0ed5b800be2136bcb8fa9c1bdf59abc957a98845/master branch.

MediumCVSS 6.4 · v3.1—No exploit Fix available
Published
Dec 9, 2020
Updated
Jun 16, 2026
EPSS
1.3% · 70th percentile
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Report tools

JSON

Action score

25

Monitor

Low priority for now.

CVSS
25 / 40 · 6.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.3%

CNA vs NVD score

NVD
6.4
CNA · snyk
7.1
0.7 point gap

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N/E:P/RL:O/RC:C

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
phpofficephpspreadsheet

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • phpoffice phpspreadsheetbefore 1.16.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (snyk). Independent of NVD's CPE analysis and usually ahead of it.

  • n/a phpoffice/phpspreadsheet

    • 0.0.0 and later · before unspecifiedaffected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Packagistphpoffice/phpexcelup to and including 1.8.2—
Packagistphpoffice/phpspreadsheetbefore 1.16.01.16.0

Same product

phpoffice: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-19277securityScan() in PHPOffice PhpSpreadsheet through 1.5.0 allows a bypass of protection mechanisms for XXE via UTF-7 encoding in a .xlsx file
    37Monitor
  • CVE-2026-45034PhpSpreadsheet: File::prohibitWrappers bypass
    36Monitor
  • CVE-2026-34084PhpSpreadsheet SSRF and RCE via PHP stream wrappers in IOFactory::load
    36Monitor
  • CVE-2024-45291Path traversal and Server-Side Request Forgery in HTML writer when embedding images is enabled in PHPSpreadsheet
    35Monitor
  • CVE-2019-12331PHPOffice PhpSpreadsheet before 1.8.0 has an XXE issue.
    35Monitor
  • CVE-2025-54370PhpSpreadsheet vulnerable to SSRF when reading and displaying a processed HTML document in the browser
    34Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Packagist:phpoffice/phpspreadsheet1.16.0Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

nvd-primary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

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We use this product, ask for help

Change log

  1. Fix✗ → ✓

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References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records