A critical member-filter bypass in the Scriban templating library lets attackers read properties and fields that a tightened sandbox policy was supposed to hide, with a CVSS 3.1 base score of 9.1.
What Is It
Scriban versions before 7.0.0 cache TypedObjectAccessor instances keyed only by Type, without accounting for changes to the associated MemberFilter. When a TemplateContext instance is reused after its MemberFilter has been tightened, the stale cached accessor is returned and members that should now be hidden remain reachable. The flaw is classified as CWE-693 (Protection Mechanism Failure).
Why It Matters
The assigning CNA, VulnCheck, rates this 9.1 CRITICAL (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N) and also publishes a CVSS 4.0 score of 9.3 CRITICAL. NVD has not yet issued its own analysis, so no NVD-assigned score exists at this time. The vector is network-reachable, low complexity, and requires no privileges and no user interaction, with high confidentiality and integrity impact. Per the advisory, an attacker can access filtered properties and fields and bypass sandbox policies across requests or tenants; making this especially relevant to multi-tenant applications that render untrusted or semi-trusted templates through a shared TemplateContext.
The CVE does not appear in CISA's Known Exploited Vulnerabilities catalog, so there is no confirmation of active exploitation at this time.
What's Vulnerable
- Product: Scriban (
pkg:nuget/scriban), vendorscriban - Affected versions: all versions before 7.0.0 (semver range
0up to, but not including,7.0.0) - Not affected: 7.0.0 and later
No CPE entries were published with this record.
Patch Status
Scriban 7.0.0 is marked unaffected and is the fixed release. Upgrade the scriban NuGet package to 7.0.0 or later. Applications that cannot upgrade immediately should avoid reusing a TemplateContext instance after modifying its MemberFilter, the reuse pattern is the precondition for the bypass. Because the CVE is not in CISA's Known Exploited Vulnerabilities catalog, no KEV required action or remediation due date applies.
The record was published 2026-08-16 by [email protected] and remains in Received status, so NVD enrichment (CPEs, primary analysis) is still pending.