CVE
magento-lts stored XSS in admin pages via tax, OAuth and PayPal fields
Affects OpenMage magento-lts before 20.18.2, and 21.0.0-beta1 before 21.0.0-beta3, where an admin role with access to Dataflow, tax, OAuth or PayPal fields can store the markup. 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
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Attacker holds an admin role with ACL access to one of the four affected areas: Dataflow profiles, tax rates, OAuth consumers, or PayPal configuration. Affected versions are magento-lts before 20.18.2, and 21.0.0-beta1 before 21.0.0-beta3. The tax full summary sink only renders when Display Full Tax Summary is enabled.
- 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? →
- 16/100 · 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? →
- Specific setups only
- 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 before 20.18.2 and 21.0.0-beta1 before 21.0.0-beta3 contains a stored cross-site scripting vulnerability because admin pages render Dataflow profile link variables, tax rate titles, OAuth consumer names, and PayPal certificate filenames without escaping. An administrator restricted to one affected area can store script that runs when another administrator, including a full administrator, opens the page, reading the form key and performing actions with that administrator's privileges.
Who should check
Teams running OpenMage magento-lts before 20.18.2 or 21.0.0-beta1 to 21.0.0-beta3, especially those with delegated admin roles and custom theme overrides of the affected templates.
Read the source excerpt
“OpenMage magento-lts before 20.18.2 and 21.0.0-beta1 before 21.0.0-beta3”
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure8/25Specific setups only, reachable over the network
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.4/10CVSS 8.4
- No patch0/5No signal
What would change the score
- Would score about 66 if added to CISA KEV
- Would score about 61 if CISA's SSVC rates exploitation active
- Would score about 23 if CISA's SSVC rates it automatable
What to do
Check whether your setup matches what the bug needs.
Attacker holds an admin role with ACL access to one of the four affected areas: Dataflow profiles, tax rates, OAuth consumers, or PayPal configuration. Affected versions are magento-lts before 20.18.2, and 21.0.0-beta1 before 21.0.0-beta3. The tax full summary sink only renders when Display Full Tax Summary is enabled.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-2026-128040 (OpenMage magento-lts before 20.18.2 Stored XSS via Admin Dataflow, Tax, OAuth, PayPal Fields), 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-2026-128040 (entry last updated 2026-11-13):
Affected:
- OpenMage magento-lts: 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):
- Attacker holds an admin role with ACL access to one of the four affected areas: Dataflow profiles, tax rates, OAuth consumers, or PayPal configuration. (source: https://github.com/OpenMage/magento-lts/security/advisories/GHSA-m858-x59w-rmp5)
- Affected versions are magento-lts before 20.18.2, and 21.0.0-beta1 before 21.0.0-beta3. (source: https://www.vulncheck.com/advisories/openmage-magento-lts-before-20.18.2-stored-xss-via-admin-dataflow-tax-oauth-paypal-fields)
- The tax full summary sink only renders when Display Full Tax Summary is enabled. (source: https://github.com/OpenMage/magento-lts/security/advisories/GHSA-m858-x59w-rmp5)
Setup: the bug is reachable in a default setup; no special feature or setting is needed.
Attacker needs: network access, high-privilege login, a user action.
CISA KEV: CVE-2026-128040 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-128040 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-m858-x59w-rmp5
- https://github.com/OpenMage/magento-lts/commit/d10314ddda9a6081bc27370b463b5f77c2e499de
- https://github.com/OpenMage/magento-lts/commit/7f7a9deaac11fd2437bb1f8065db152a4b620609
- https://github.com/OpenMage/magento-lts/commit/62d2885fa6e7a4454e3a5c7765a6a5ca0085ecc1
- https://github.com/OpenMage/magento-lts/commit/e97e257b8f8d74d2e52dbf28caa211c262ff26be
- https://www.vulncheck.com/advisories/openmage-magento-lts-before-20.18.2-stored-xss-via-admin-dataflow-tax-oauth-paypal-fields
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-2026-128040
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-2026-128040"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- OpenMage magento-lts
fixed in 20.18.2
- OpenMage magento-lts
From 21.0.0-beta1 · fixed in 21.0.0-beta3
Evidence 8
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 5
- Patch
- Patch
- Patch
- Patch
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-128040
Is CVE-2026-128040 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?
Markup stored in Dataflow profiles, tax rates, OAuth consumers, or PayPal configuration runs in another administrator's session. There it can read the form key and perform any action that administrator is allowed to perform.Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-128040?
magento-lts: 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?
magento-lts versions before 20.18.2, and 21.0.0-beta1 before 21.0.0-beta3. The attacker needs an admin role with access to one of the four affected areas. The tax full summary sink only renders when Display Full Tax Summary is enabled, which is not the default, so check that setting along with the installed magento-lts version.Source: github.com, vulncheck.com
How do I fix CVE-2026-128040?
Upgrade magento-lts to 20.18.2, or to 21.0.0-beta3 on the 21.0.0 beta line.Source: github.com, vulncheck.com