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CVE-2026-34084

Phpoffice Phpspreadsheet remote code execution

9.8 CRITICALPublic exploitEPSS 0.78%
  1. Published5 May 2026

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 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Phpoffice Phpspreadsheet≥ 2.0.0 < 2.1.15 · ≥ 2.2.0 < 2.4.4 · ≥ 3.3.0 < 3.10.4 · ≥ 4.0.0 < 5.6.0

Remediation

Fixed in
Phpoffice Phpspreadsheet≥ 2.1.15

References

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Frequently asked

Is CVE-2026-34084 being actively exploited?

CVE-2026-34084 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.78%.

How severe is CVE-2026-34084?

CVE-2026-34084 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.78% probability of exploitation.

Which products are affected by CVE-2026-34084?

Affected products include Phpoffice Phpspreadsheet.

How do I fix CVE-2026-34084?

Upgrade affected software to a fixed version, for example Phpoffice Phpspreadsheet 2.1.15 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-34084 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.