Security Digest · Vulnerability record
CVE-2026-34084: PhpSpreadsheet has SSRF/RCE in IOFactory::load when $filename is user controlled
PhpSpreadsheet is a library for reading and writing spreadsheet files.
CVSS 9.2 Critical EPSS 0.8% · p55
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.8%, percentile 55: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 55% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
phpoffice/phpspreadsheet(Composer (PHP)) >= 4.0.0, <= 5.5.0, fixed in 5.6.0;phpoffice/phpspreadsheet(Composer (PHP)) >= 3.3.0, <= 3.10.3, fixed in 3.10.4;phpoffice/phpspreadsheet(Composer (PHP)) >= 2.2.0, <= 2.4.3, fixed in 2.4.4;phpoffice/phpspreadsheet(Composer (PHP)) >= 2.0.0, <= 2.1.14, fixed in 2.1.15. Check your lockfile, including transitive dependencies.
What it is
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 isfile() 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.
From the GitHub advisory
The usage of isfile, used to verify if the $filename is indeed an actual file, by all(?) Reader implementations (inside the helper function File::assertFile) is php-wrapper aware, for any php wrappers implementing stat(). The 3 wrappers ftp://, phar:// and ssh2.sftp://, all satisfy this requirement - 2 of which are shown in the PoC below.
This results in a SSRF, at "best", and RCE at worse.
This was tested against the latest release - but the issue seems to go back a while from a first quick check (still present in v1.30.2).
PoC To reproduce the vulnerable behavior, the following scripts were used:
php.ini file, only needed to build the malicious phar, not necessary to exploit on a deployed instance of the library:
Weakness type: CWE-502, CWE-918.
Product: phpoffice/phpspreadsheet (Composer (PHP)) · Assigned by: GitHub_M · Published: 2026-05-05
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Composer (PHP) | phpoffice/phpspreadsheet | >= 4.0.0, <= 5.5.0 | 5.6.0 |
| Composer (PHP) | phpoffice/phpspreadsheet | >= 3.3.0, <= 3.10.3 | 3.10.4 |
| Composer (PHP) | phpoffice/phpspreadsheet | >= 2.2.0, <= 2.4.3 | 2.4.4 |
| Composer (PHP) | phpoffice/phpspreadsheet | >= 2.0.0, <= 2.1.14 | 2.1.15 |
| Composer (PHP) | phpoffice/phpspreadsheet | <= 1.30.2 | 1.30.3 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| PHPOffice | PhpSpreadsheet | >= 4.0.0, <= 5.5.0, >= 3.3.0, <= 3.10.3, >= 2.2.0, <= 2.4.3, >= 2.0.0, <= 2.1.14, <= 1.30.2 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 4.0 | 9.2 Critical | 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 |
| GitHub | 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 |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: present (depends on deployment conditions)
- Privileges required: none (no login)
- User interaction: none
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.78% probability of exploitation activity in the next 30 days; percentile 55.
Timeline
- — GitHub-reviewed advisory GHSA-q4q6-r8wh-5cgh published (critical)
- — CVE record last updated
- — CVE record published by GitHub_M
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-q4q6-r8wh-5cgh github.com
- CVE.org record CVE-2026-34084 cve.org
- NVD entry CVE-2026-34084 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- php.net php.net
Critical Composer (PHP) advisories · Today’s Security Digest