PHPSpreadsheet has a patch bypass for CVE-2026-34084

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

9.2 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-45034: 0.46% estimated exploitation activity in the next 30 days; percentile 40.11 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary CVE-2026-34084 was patched by the helper File::prohibitWrappers. The helper calls parseurl($filename, PHPURLSCHEME) and then checks isstring($scheme) && strlen($scheme) 1 to reject stream wrappers such as phar://, php://, data:// or expect://. The check is not equivalent to "does the path contain a wrapper". When the input has the form phar:///path/file.phar/inner with three or more slashes after the scheme, parseurl returns boolean false instead of returning the scheme string. The isstring($scheme) branch is therefore skipped, the helper returns without throwing, and the caller proceeds. PHP's stream layer, however, still treats phar:///... as a valid phar wrapper and opens the underlying phar file. The result is that IOFactory::load($attackerPath) walks past the patch and still touches the phar wrapper. On PHP 7.x, simply reaching the phar wrapper via isfile is enough for PHP to automatically deserialize the phar metadata, which in turn invokes the magic methods wakeup and…

Published by the source

8 Jun 2026, 23:00 UTC

Last modified by the source

8 Jun 2026, 23:00 UTC

Source last checked

26 Oct 2026, 14:48 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-87m4-826x-3crx

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# Patch Next advisory brief: CVE-2026-45034

Advisory: PHPSpreadsheet has a patch bypass for CVE-2026-34084
IDs: CVE-2026-45034, GHSA-87m4-826x-3crx
Record: https://patchnext.com/advisories/cve-2026-45034 (revision 1, source checked 26 Oct 2026, 14:48 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: phpoffice/phpspreadsheet 1.30.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist phpoffice/phpspreadsheet: affected <= 1.30.4; fixed in 1.30.5

## Suggested inspection (read-only)
- Packagist phpoffice/phpspreadsheet: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on phpoffice/phpspreadsheet.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-87m4-826x-3crx (GitHub-reviewed advisory GHSA-87m4-826x-3crx lists affected ranges: Packagist phpoffice/phpspreadsheet >=0 <=1.30.4)

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