CVE
Contao 4.0.0 before 5.3.54, 5.4.0 before 5.7.17, and 6.0.0 before 6.0.6 Filemount Bypass via Edit-Multiple
- Exploited
- No known exploitation
- Fix
- Fixed in 5.3.54, 5.7.17, 6.0.6
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Backend user has a filemount restricted to specific folders User holds the table-wide protected or syncExclude field permission Contao version in the affected ranges
- 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? →
- 15/100 · 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
Contao is affected: backend users restricted to certain filemounts can change folders outside their allowed area through the file manager's Edit-Multiple operation. An attacker with low-privilege backend login and the protected or syncExclude permission can reach this remotely over the network and use it to publish protected folders for public download or exclude them from synchronization.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
Contao 4.0.0 before 5.3.54, 5.4.0 before 5.7.17, and 6.0.0 before 6.0.6 contains an access control bypass vulnerability that allows filemount-restricted backend users to modify folders outside their filemount via the file manager Edit-Multiple operation. Attackers holding the protected or syncExclude field permission can submit outside folder paths in the IDS parameter to publish protected folders or exclude them from DBAFS synchronization, exposing files for public download.
Who should check
Teams running Contao 4.0.0 to before 5.3.54, 5.4.0 to before 5.7.17, or 6.0.0 to before 6.0.6 that use restricted backend filemounts and grant the protected or syncExclude field permission
Read the source excerpt
“Contao 4.0.0 before 5.3.54, 5.4.0 before 5.7.17, and 6.0.0 before 6.0.6”
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
- Severity7.1/10CVSS 7.1
- No patch0/5No signal
What would change the score
- Would score about 65 if added to CISA KEV
- Would score about 60 if CISA's SSVC rates exploitation active
- Would score about 22 if CISA's SSVC rates it automatable
What to do
Check whether your setup matches what the bug needs.
Backend user has a filemount restricted to specific folders User holds the table-wide protected or syncExclude field permission Contao version in the affected rangesUpgrade to a fixed version: 5.3.54, 5.7.17, 6.0.6.
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-2026-126662 (Contao 4.0.0 before 5.3.54, 5.4.0 before 5.7.17, and 6.0.0 before 6.0.6 Filemount Bypass via Edit-Multiple), 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-2026-126662 (entry last updated 2026-11-11):
Affected:
- Contao Contao: from 4.0.0, fixed in 5.3.54; from 5.4.0-RC1, fixed in 5.7.17; from 6.0.0-RC1, fixed in 6.0.6
Fixed versions: 5.3.54, 5.7.17, 6.0.6.
Conditions (all must be true for the bug to be hit):
- Backend user has a filemount restricted to specific folders (source: https://github.com/contao/contao/security/advisories/GHSA-9jfh-v443-w3fj)
- User holds the table-wide protected or syncExclude field permission (source: https://github.com/contao/contao/security/advisories/GHSA-9jfh-v443-w3fj)
- Contao version in the affected ranges (source: https://www.vulncheck.com/advisories/contao-4.0.0-before-5.3.54-5.4.0-before-5.7.17-and-6.0.0-before-6.0.6-filemount-bypass-via-edit-multiple)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, low-privilege login, no user action.
CISA KEV: CVE-2026-126662 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-126662 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/contao/contao/security/advisories/GHSA-9jfh-v443-w3fj
- https://github.com/contao/contao/commit/c01898f99c5d5af50a227ee85f27270c5427f900
- https://github.com/contao/contao/commit/a104202df2b532bb64805a0856fc94bb0bddbb66
- https://github.com/contao/contao/commit/240e169441796bb703819ee0e22728708f946b70
- https://github.com/contao/contao/releases/tag/5.3.54
- https://github.com/contao/contao/releases/tag/5.7.17
- https://github.com/contao/contao/releases/tag/6.0.6
- https://github.com/contao/contao/blob/5.3.53/core-bundle/contao/drivers/DC_Folder.php#L1716-L1720
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-2026-126662
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-2026-126662"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- Contao Contao
From 4.0.0 · fixed in 5.3.54; From 5.4.0-RC1 · fixed in 5.7.17; From 6.0.0-RC1 · fixed in 6.0.6
Evidence 11
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 8
- Patch
- Patch
- Patch
- Repository
- Repository
Show all 8 sourcesShow fewer sources
- Repository
- Repository
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-126662
Is CVE-2026-126662 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 backend user whose filemount is limited to certain folders can, through the edit-multiple feature, mark folders outside that filemount as protected or exclude them from DBAFS synchronization. Publishing a protected folder can expose its files for public download.Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-126662?
Contao: from 4.0.0 before 5.3.54; from 5.4.0-RC1 before 5.7.17; from 6.0.0-RC1 before 6.0.6.Source: cve.now feed data
Am I affected, and how do I check?
Contao 4.0.0 before 5.3.54, 5.4.0 before 5.7.17, and 6.0.0 before 6.0.6 are in the affected ranges. The bug requires a backend user with a filemount restricted to specific folders who also holds the table-wide protected or syncExclude field permission; check the installed Contao version and that user's permissions and filemount settings.Source: github.com, vulncheck.com
How do I fix CVE-2026-126662?
Upgrade to Contao 5.3.54, 5.7.17, or 6.0.6, matching your release line. No workaround is listed in the facts.Source: github.com, vulncheck.com