CVE-2026-34084

Description

PhpSpreadsheet is a library for reading and writing spreadsheet files. In versions 1.30.2 and earlier, 2.0.0 through 2.1.14, 2.2.0 through 2.4.3, 3.3.0 through 3.10.3, and 4.0.0 through 5.5.0, when the filename argument to IOFactory::load() is user-controlled, an attacker can supply a PHP stream wrapper path (such as phar://, ftp://, or ssh2.sftp://) that passes the is_file() check in File::assertFile(). The phar:// wrapper triggers deserialization of the PHAR metadata, which can lead to remote code execution if a suitable gadget chain is available in the application. The ftp:// and ssh2.sftp:// wrappers can be used for server-side request forgery. This issue has been fixed in versions 1.30.3, 2.1.15, 2.4.4, 3.10.4, and 5.6.0.

CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0023

Probability of exploitation

0.45%

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-502 Deserialization of Untrusted Data

CWE-918 Server-Side Request Forgery (SSRF)

Affected Products

Vendor	Product	Versions
phpoffice	phpspreadsheet	< 1.30.3
phpoffice	phpspreadsheet	2.0.0 — 2.1.15
phpoffice	phpspreadsheet	2.2.0 — 2.4.4
phpoffice	phpspreadsheet	3.3.0 — 3.10.4
phpoffice	phpspreadsheet	4.0.0 — 5.6.0

References

Advisories & Patches

https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-q4q6-r8wh-5cgh https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-q4q6-r8wh-5cgh

Exploits

https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-q4q6-r8wh-5cgh https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-q4q6-r8wh-5cgh

Frequently Asked Questions

What is CVE-2026-34084? +

PhpSpreadsheet is a library for reading and writing spreadsheet files. In versions 1.30.2 and earlier, 2.0.0 through 2.1.14, 2.2.0 through 2.4.3, 3.3.0 through 3.10.3, and 4.0.0 through 5.5.0, when the filename argument to IOFactory::load() is user-controlled, an attacker can supply a PHP stream wrapper path (such as phar://, ftp://, or ssh2.sftp://) that passes the is_file() check in File::assertFile(). The phar:// wrapper triggers deserialization of the PHAR metadata, which can lead to remote code execution if a suitable gadget chain is available in the application. The ftp:// and ssh2.sftp:// wrappers can be used for server-side request forgery. This issue has been fixed in versions 1.30.3, 2.1.15, 2.4.4, 3.10.4, and 5.6.0. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-34084? +

CVE-2026-34084 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0023, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-34084? +

CVE-2026-34084 affects products from phpoffice, specifically: phpspreadsheet. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-34084? +

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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