CVE-2026-46696 October CMS: Safe Mode Sandbox Bypass via Session Store and Forwarded Builder Calls
A backend user with markup editing access can bypass Twig sandbox restrictions to read arbitrary database values and forge superuser sessions.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46696?
CVE-2026-46696 is a low-severity vulnerability in octobercms system, published on 14 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
October System provides the system module for October Content Management System. Versions prior to 3.7.17 and 4.2.21 have a vulnerability in the Twig sandbox security policy that allowed a chained bypass when `cms.safe_mode` is enabled. The Laravel session store was exposed to Twig with unrestricted method access, and raw SQL methods reachable through Eloquent's `__call` forwarding were not blocked across the full builder chain. When combined, a backend user with CMS markup editing access could read arbitrary database values via raw SQL expressions and write to the backend authentication session key, forging a backend session as another existing user. The scope of impact is narrow. Safe Mode is a niche feature, primarily used for demo installations and multi-tenant or shared-editor scenarios where untrusted users are deliberately granted access to the CMS markup editor. Standard production deployments do not enable Safe Mode, because under normal October CMS guidance backend access - including markup editing - is restricted to trusted administrators, and direct PHP injection through markup is already possible without Safe Mode in that configuration. This issue only affects sites that meet all of the following conditions: `cms.safe_mode` is enabled (a deliberate opt-in for demos or untrusted-editor scenarios; the site has at least one backend user with CMS markup editing access who is not intended to be trusted as a full administrator; and the site has at least one existing superuser account whose session the lower-privileged user can impersonate. The vulnerability has been patched in v3.7.17 and v4.2.21. The Laravel session store is now wrapped in a proxy that exposes only an explicit subset of read/write methods and rejects writes to reserved session key prefixes (`admin_auth`, `october_auth`, `login_*`, `_token`, and other framework internals). Raw SQL and subquery methods (`selectRaw`, `whereRaw`, `orderByRaw`, `joinSub`, and related) are now blocked on `Query\Builder`, `Eloquent\Builder`, and `Eloquent\Model` so the blocklist is consistent across the `__call` forwarding chain. All sites that enable `cms.safe_mode` are encouraged to upgrade to the latest patched version. A workaround is available. Restrict CMS markup editing access to fully trusted administrators only - the standard October CMS recommendation for any deployment. Note that disabling `cms.safe_mode` is not a workaround; Safe Mode is the boundary this issue affects, and disabling it removes the only sandbox between markup editors and the server.
Which versions are affected by CVE-2026-46696?
4 open source packages ship an affected version, including october/system.
| Package | Affected | Fixed in |
|---|---|---|
october/system Packagist | All versions | 3.7.17 |
october/system Packagist | All versions | 3.7.17 |
october/system Packagist | From 4.0.0 | 4.2.23 |
october/system Packagist | From 4.0.0 | 4.2.23 |
How do I fix CVE-2026-46696?
Upgrade october/system to a fixed version for your release line: 3.7.17 or 4.2.23.
Is CVE-2026-46696 being exploited?
There is no known exploitation of CVE-2026-46696 in the wild and no public exploit code.
Sources
Also known as GHSA-xv9m-fm3w-8w5x.