CVE-2026-59931: SSRF (CVSS 7.7)

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.

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CVSS v3.1 Score

7.7

HIGH

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

EPSS — Exploit Prediction

0.0053

Probability of exploitation

0.42%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-918 Server-Side Request Forgery (SSRF)

References

Other References

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. It has a CVSS v3.1 base score of 7.7 (HIGH).

How severe is CVE-2026-59931? +

CVE-2026-59931 has a CVSS v3.1 score of 7.7 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0053, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-59931? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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