CVE-2026-34084
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedPhpSpreadsheet 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidencePhpSpreadsheet's IOFactory::load() fails to properly validate user-supplied filenames, allowing PHP stream wrapper paths (phar://, ftp://, ssh2.sftp://) to bypass the is_file() check in File::assertFile(). The phar:// wrapper triggers PHAR metadata deserialization, enabling RCE if a suitable gadget chain exists in the application context. The ftp:// and ssh2.sftp:// wrappers enable SSRF attacks.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 1.30.3>= 2.0.0, < 2.1.15>= 2.2.0, < 2.4.4>= 3.3.0, < 3.10.4>= 4.0.0, < 5.6.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify Phpspreadsheet versionLocate the installed Phpspreadsheet package version in your project's composer.json or vendor/composer/installed.json file, or run 'composer show phpoffice/phpspreadsheet' to display the installed versionAffected if The installed version falls into any of these ranges: < 1.30.3, >= 2.0.0 and < 2.1.15, >= 2.2.0 and < 2.4.4, >= 3.3.0 and < 3.10.4, or >= 4.0.0 and < 5.6.0
-
Verify IOFactory::load() usageSearch your codebase for calls to \PhpOffice\PhpSpreadsheet\IOFactory::load() method and examine the source of the filename parameter being passed to itAffected if IOFactory::load() is called with a filename argument derived from user-supplied input
-
Inspect filename handling for stream wrappersReview the code paths that provide filenames to IOFactory::load() and verify whether any validation exists that explicitly blocks or sanitizes stream wrapper protocols (phar://, ftp://, ssh2.sftp://)Affected if User-controlled filenames can reach IOFactory::load() without stripping or blocking stream wrapper protocols
-
Check for is_file() validation bypass potentialExamine the File::assertFile() method in your Phpspreadsheet library or confirm that stream wrapper filenames bypass local file existence checksAffected if Your application accepts filenames containing phar://, ftp://, or ssh2.sftp:// protocols for processing by IOFactory::load()
You are affected if your Phpspreadsheet version is within any of the vulnerable ranges AND your application passes user-supplied filenames (without stream wrapper filtering) to IOFactory::load().
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.30.32.1.152.4.4
Upgrade PhpSpreadsheet to versions 1.30.3, 2.1.15, 2.4.4, 3.10.4, or 5.6.0. If upgrading is not immediately feasible, ensure user-controlled input is never passed directly to IOFactory::load() and implement strict allowlist validation on file paths.
Upgrade to minimum fixed version for your branch: 1.30.3, 2.1.15, 2.4.4, 3.10.4, or 5.6.0 (preferably latest 5.x)
- 1. Identify current PhpSpreadsheet version by running `composer show phpoffice/phpspreadsheet` or checking composer.json
- 2. Based on current version, run `composer require phpoffice/phpspreadsheet:<fixed_version>` with: <1.30.3 upgrade to 1.30.3; >=2.0.0 <2.1.15 upgrade to 2.1.15; >=2.2.0 <2.4.4 upgrade to 2.4.4; >=3.3.0 <3.10.4 upgrade to 3.10.4; >=4.0.0 upgrade to 5.6.0 or latest
- 3. Run `composer update phpoffice/phpspreadsheet` to apply the upgrade
- 4. Verify the installed version matches the target fixed version using `composer show phpoffice/phpspreadsheet`
- 5. Test the application thoroughly to ensure functionality remains intact
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation2.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,928.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-34084 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-34084 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data