CyberSecBulletin
CVE-2026-128046NVD status: Deferred

magento-lts: Incomplete List of Disallowed Inputs

Published Updated By the CyberSecBulletin desk

CVE-2026-128046 is a high-severity incomplete list of disallowed inputs vulnerability in magento-lts from OpenMage, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 20.18.2, 21.0.0-beta3 as the first without the flaw, so updating magento-lts to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.64% chance of exploitation within 30 days, higher than 51% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update magento-lts to 20.18.2 or 21.0.0-beta3, whichever matches your release line, or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
OpenMagemagento-lts20.17.0 up to, but not including, 20.18.2; 21.0.0-beta1 up to, but not including, 21.0.0-beta320.18.2, 21.0.0-beta3

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (vulncheck.com).

Scoring systemScoreSeverityScored by
CVSS 4.09.2CriticalCNA (vulncheck.com)
CVSS 3.18.1HighCNA (vulncheck.com)

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Incomplete List of Disallowed Inputs

The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.

How developers prevent this class of flaw

  • Do not rely exclusively on detecting disallowed inputs. There are too many variants to encode a character, especially when different environments are used, so there is a high likelihood of missing some variants. Only use detection of disallowed inputs as a mechanism for detecting suspicious activity. Ensure that you are using other protection mechanisms that only identify good input - such as lists of allowed inputs - and ensure that you are properly encoding your outputs.

More Incomplete List of Disallowed Inputs vulnerabilities (CWE-184)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).

References

Other vulnerabilities in magento-lts

All magento-lts vulnerabilities

Recent Incomplete List of Disallowed Inputs vulnerabilities

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