CVE-2026-59931: PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. In versions 4.0.0 through 5.8.0, 3.3.0 through 3.10.6, 2.2.0 through 2...

Description

PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. In versions 4.0.0 through 5.8.0, 3.3.0 through 3.10.6, 2.2.0 through 2.4.6, 2.0.0 through 2.1.17, and all releases up to and including 1.30.5, the WEBSERVICE() domain whitelist can be bypassed via an HTTP redirect (SSRF). In Calculation/Web/Service.php, the webService() method validates a URL's host against the whitelist set via Spreadsheet::setDomainWhiteList(), then fetches content with file_get_contents($url, false, $ctx); because PHP's HTTP stream wrapper follows 301/302 redirects automatically (up to 20 hops) and the redirect target is never re-validated, an attacker who can trigger a redirect from a whitelisted domain can reach arbitrary URLs, including internal addresses. An attacker able to upload XLSX files to an application that uses setDomainWhiteList() and getCalculatedValue() can achieve a full-read SSRF, returning up to 32,767 bytes of the response body as a cell's calculated value, which enables exfiltration of cloud metadata (AWS/GCP/Azure credentials via http://169.254.169.254/), access to internal-only services, and internal port scanning (the port is not validated). This issue has been fixed in versions 5.8.1, 3.10.7, 2.4.7, 2.1.18, and 1.30.6.

Metrics

CVSS 3.1

7.7/10

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

EPSS Probability

0.53%

41.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-918

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
PHPOffice	PhpSpreadsheet	>= 4.0.0, < 5.8.1; >= 3.3.0, < 3.10.7; >= 2.2.0, < 2.4.7; >= 2.0.0, < 2.1.18; < 1.30.6

References

Timeline

Published: Jul 28, 2026
Last Modified: Jul 30, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-59931?

PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. In versions 4.0.0 through 5.8.0, 3.3.0 through 3.10.6, 2.2.0 through 2.4.6, 2.0.0 through 2.1.17, and all releases up to and including 1.30.5, the WEBSERVICE() domain whitelist can be bypassed via an HTTP redirect (SSRF). In Calculation/Web/Service.php, the webService() method validates a URL's host against the whitelist set via Spreadsheet::setDomainWhiteList(), then fetches content with file_get_contents($url, false, $ctx); because PHP's HTTP stream wrapper follows 301/302 redirects automatically (up to 20 hops) and the redirect target is never re-validated, an attacker who can trigger a redirect from a whitelisted domain can reach arbitrary URLs, including internal addresses. An attacker able to upload XLSX files to an application that uses setDomainWhiteList() and getCalculatedValue() can achieve a full-read SSRF, returning up to 32,767 bytes of the response body as a cell's calculated value, which enables exfiltration of cloud metadata (AWS/GCP/Azure credentials via http://169.254.169.254/), access to internal-only services, and internal port scanning (the port is not validated). This issue has been fixed in versions 5.8.1, 3.10.7, 2.4.7, 2.1.18, and 1.30.6.

How severe is CVE-2026-59931?

CVE-2026-59931 has a CVSS score of 7.7/10 (HIGH severity). The EPSS model estimates a 0.53% probability of exploitation in the next 30 days.

How do I fix CVE-2026-59931?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →