GHSA-rxj4-h86g-25gc: phpoffice/phpspreadsheet (CVE-2026-108357)

Package	Ecosystem	Affected	Fixed in
phpoffice/phpspreadsheet	Packagist	>=4.0.0, <5.10.0 \|\| >=3.3.0, <3.10.8	5.10.0, 3.10.8

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

PhpSpreadsheet versions 3.3.0 up to 3.10.8 and 4.0.0 up to 5.10.0 are affected. The SpreadsheetML XML reader can be tricked by a specially encoded file into skipping its check for XML declarations. An attacker who can get an application to process such a file can cause denial of service through entity expansion on all PHP versions, and can read local files or make server-side requests on PHP below 8.0 or when LIBXML_NOENT is used. Upgrade to 3.10.8 or 5.10.0, which contain fixes.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
8.8	High	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:L/SI:N/SA:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0046, the 40th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 13:53 UTC First seen by agentprime
31 Oct 2026, 13:53 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.