CVE
magento-lts remote code execution via file upload in custom options
Affects OpenMage magento-lts 20.17.0 before 20.18.2 and 21.0.0-beta1 before 21.0.0-beta3 when a File custom option has an empty allowed-extension list. Fixed in 20.18.2 and 21.0.0-beta3.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 20.18.2, 21.0.0-beta3
- Who is exposed
- Default setups
Do first: Check every install: default setups are affected.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 31/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Default setups
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
OpenMage magento-lts 20.17.0 before 20.18.2 and 21.0.0-beta1 before 21.0.0-beta3 contains an unrestricted file upload vulnerability because the general/file/protected_extensions blocklist omits phar, php8, and phps. Unauthenticated attackers can upload a .phar file through a product File custom option to a predictable media/custom_options path and request it directly to execute code on servers that map .phar to PHP and serve that directory.
Who should check
Stores running OpenMage magento-lts from 20.17.0 before 20.18.2, or 21.0.0-beta1 before 21.0.0-beta3, that sell products with File custom options.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure22/25Default setups, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity9.2/10CVSS 9.2
- No patch0/5No signal
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
What to do
Check every install: default setups are affected.
Upgrade to a fixed version: 20.18.2, 21.0.0-beta3.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-128046 (OpenMage magento-lts 20.17.0 before 20.18.2 Unrestricted File Upload RCE via Custom Options), using the cve.now data below.
Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.
What cve.now has for CVE-2026-128046 (entry last updated 2026-11-13):
Affected:
- OpenMage magento-lts: from 20.17.0, fixed in 20.18.2
- OpenMage magento-lts: from 21.0.0-beta1, fixed in 21.0.0-beta3
Fixed versions: 20.18.2, 21.0.0-beta3.
Conditions (all must be true for the bug to be hit):
- A product has a File custom option with an empty allowed-extension list. (source: https://github.com/OpenMage/magento-lts/security/advisories/GHSA-4fxg-469f-r6fc)
- The web server maps .phar (or .php8 / .phps) to the PHP handler. (source: https://github.com/OpenMage/magento-lts/security/advisories/GHSA-4fxg-469f-r6fc)
- The web server serves the media/custom_options/ directory (nginx, or Apache without AllowOverride). (source: https://github.com/OpenMage/magento-lts/security/advisories/GHSA-4fxg-469f-r6fc)
Setup: the bug is reachable in a default setup; no special feature or setting is needed.
Attacker needs: network access, no login, no user action.
CISA KEV: CVE-2026-128046 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-128046 only. If you also check another CVE, look up its own KEV status; never assume it from this one.
How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.
Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/OpenMage/magento-lts/security/advisories/GHSA-4fxg-469f-r6fc
- https://github.com/OpenMage/magento-lts/commit/ba76b2346fe1e380f39c23e68ccb818d7324d24f
- https://github.com/OpenMage/magento-lts/commit/5b6f985785245a964aa3dc78609f6af44d9d5e27
- https://github.com/OpenMage/magento-lts/commit/dd692b825ba50f196bcc20ae67fbed48dd95da56
- https://www.vulncheck.com/advisories/openmage-magento-lts-20.17.0-before-20.18.2-unrestricted-file-upload-rce-via-custom-options
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.
Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.
Entry: https://cve.now/CVE-2026-128046
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-128046"}.Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
Affected versions
- OpenMage magento-lts
From 20.17.0 · fixed in 20.18.2
- OpenMage magento-lts
From 21.0.0-beta1 · fixed in 21.0.0-beta3
Evidence 7
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-128046
Is CVE-2026-128046 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
A File custom option with an empty allowed-extension list lets a visitor without logging in upload a PHP file. If the web server runs that file, the visitor can run code on the application server, which can lead to full compromise of the server.Source: github.com
Which versions are affected by CVE-2026-128046?
magento-lts: from 20.17.0 before 20.18.2. magento-lts: from 21.0.0-beta1 before 21.0.0-beta3.Source: cve.now feed data
Am I affected, and how do I check?
The bug needs three things: a product with a File custom option that has an empty allowed-extension list, a web server that maps .phar (or .php8 or .phps) to the PHP handler, and a web server that serves the media/custom_options/ directory, as nginx does or Apache does without AllowOverride. Check the magento-lts version in your installation, then review the custom option settings, the PHP handler mappings, and the web server configuration for media/custom_options/.Source: github.com
How do I fix CVE-2026-128046?
Upgrade to 20.18.2 or later on the 20.x line, or to 21.0.0-beta3 or later on the 21 beta line.Source: github.com