Grav: UserInterface offsetget/offsetexists allow-listed in Twig sandbox let editor-authored content leak hashed_password and 2FA secrets via offsetGet()

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-76839: 0.34% estimated exploitation activity in the next 30 days; percentile 27.77 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary system/config/security.yaml's Twig sandbox policy allow-lists offsetget and offsetexists for Grav\Common\User\Interfaces\UserInterface. The concrete Grav\Common\User\DataUser\User class does not filter which fields offsetGet() returns, so any sandboxed template with access to a User object can read hashedpassword, secret (2FA seed), and twofasecret directly, bypassing the redaction Grav's own code applies everywhere else. The core evidence, from Grav's own code system/src/Grav/Common/User/DataUser/User.php: system/config/security.yaml: This is the same vulnerability shape as two already-fixed issues in this file (GHSA-j274-39qw-32c9 and GHSA-mc5q-6hpj-rp7j -- both a raw, unfiltered data-access path bypassing an intended redaction) recurring on a third class neither fix covered. Live, end-to-end verification Built a real Twig\Environment wired with the real Twig\Extension\SandboxExtension, policed by Grav's own GravSecurityPolicy class, constructed directly from values parsed…

Published by the source

17 Sep 2026, 20:27 UTC

Last modified by the source

17 Sep 2026, 20:45 UTC

Source last checked

26 Oct 2026, 14:53 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-3jhr-mxmx-38cx

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-3jhr-mxmx-38cx

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# Patch Next advisory brief: CVE-2026-76839

Advisory: Grav: UserInterface offsetget/offsetexists allow-listed in Twig sandbox let editor-authored content leak hashed_password and 2FA secrets via offsetGet()
IDs: CVE-2026-76839, GHSA-3jhr-mxmx-38cx
Record: https://patchnext.com/advisories/cve-2026-76839 (revision 3, source checked 26 Oct 2026, 14:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: getgrav/grav 2.0.16. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist getgrav/grav: affected <= 2.0.15; fixed in 2.0.16

## Suggested inspection (read-only)
- Packagist getgrav/grav: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on getgrav/grav.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-3jhr-mxmx-38cx (OSV record GHSA-3jhr-mxmx-38cx lists affected ranges: Packagist getgrav/grav >=0 <2.0.16 (fixed))
- Verified: https://github.com/advisories/GHSA-3jhr-mxmx-38cx (GitHub-reviewed advisory GHSA-3jhr-mxmx-38cx lists affected ranges: Packagist getgrav/grav >=0 <=2.0.15)

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