ApostropheCMS: Authenticated projection-exclusion prototype-member deletion in @apostrophecms/db-connect causes process-wide denial of service

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ApostropheCMS is an open-source Node.js content management system. Prior to 1.1.0 of db-connect and 4.33.0 of ApostropheCMS, an account with view-draft access can submit a projection exclusion path that traverses through a constructor prototype chain to a shared prototype member when a consumer uses a SQLite, PostgreSQL, or multipostgres adapter and has a matching document. Every editing role has view-draft access, while guestApiAccess broadens this prerequisite to any logged-in account. The unsetNestedField helper then deletes the shared runtime member, causing persistent process-wide integrity and availability effects; the default MongoDB adapter is not affected. This issue is fixed in db-connect 1.1.0 and ApostropheCMS 4.33.0.

Source published

20 Oct 2026 17:25:44 UTC

Source modified

20 Oct 2026 17:43:12 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

ApostropheCMS is an open-source Node.js content management system. Prior to 1.1.0 of db-connect and 4.33.0 of ApostropheCMS, an account with view-draft access can submit a projection exclusion path that traverses through a constructor prototype chain to a shared prototype member when a consumer uses a SQLite, PostgreSQL, or multipostgres adapter and has a matching document. Every editing role has view-draft access, while guestApiAccess broadens this prerequisite to any logged-in account. The unsetNestedField helper then deletes the shared runtime member, causing persistent process-wide integrity and availability effects; the default MongoDB adapter is not affected. This issue is fixed in db-connect 1.1.0 and ApostropheCMS 4.33.0.

Source published

Oct 20, 2026, 5:25:44 PM (timezone not stated)

Source modified

Oct 20, 2026, 5:43:12 PM (timezone not stated)

Observed here

7 Nov 2026 04:34:36 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

ApostropheCMS is an open-source Node.js content management system. Prior to 1.1.0 of db-connect and 4.33.0 of ApostropheCMS, an account with view-draft access can submit a projection exclusion path that traverses through a constructor prototype chain to a shared prototype member when a consumer uses a SQLite, PostgreSQL, or multipostgres adapter and has a matching document. Every editing role has view-draft access, while guestApiAccess broadens this prerequisite to any logged-in account. The unsetNestedField helper then deletes the shared runtime member, causing persistent process-wide integrity and availability effects; the default MongoDB adapter is not affected. This issue is fixed in db-connect 1.1.0 and ApostropheCMS 4.33.0.

Source published

20 Oct 2026 18:17:20 UTC

Source modified

20 Oct 2026 19:53:10 UTC

Observed here

25 Oct 2026 05:17:18 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

## Summary `@apostrophecms/db-connect` ships an in-memory MongoDB emulation used by its SQLite, PostgreSQL, and multipostgres adapters. Its `unsetNestedField` helper walks an attacker-controlled dotted field path with no segment validation and calls `delete` on the resolved property. A low-privileged authenticated user (any role holding `view-draft`, which every editor and contributor has; reduced to any logged-in user when `guestApiAccess` is enabled) can send a piece-type REST GET request whose `project` query builder contains an exclusion key such as `constructor.prototype.hasOwnProperty`. On a SQLite or PostgreSQL adapter this key reaches `unsetNestedField`, which resolves `Object.prototype` and deletes a shared runtime method. Because that method is shared across the whole Node process, the deletion breaks request handling for every tenant and user until the process is restarted, giving a single request a persistent denial of service. ## Root Cause The projection query builder laundens only projection values, never projection keys, so an arbitrary dotted key survives to the database layer. On the SQLite and PostgreSQL adapters an exclusion projection is applied in JavaScript by `applyProjection`, which for each excluded field calls `unsetNestedField(result, field)`. `unsetNestedField` splits the field on `.` and walks the resulting segments with no guard: unlike its sibling `setNestedField`, it does not even block a literal `__proto__`, and neither helper blocks `constructor` or `prototype`. Because the working object is a plain object produced by `JSON.parse(JSON.stringify(doc))`, its `constructor` resolves to the global `Object`, so a path of `constructor.prototype.<member>` reaches the shared `Object.prototype` and deletes a core, configurable method. The violated invariant is that untrusted input must never be able to traverse into and mutate shared prototype objects. ```text Affected functions (repository-relative paths): - unsetNestedField packages/db-connect/lib/shared.js:119-129 (no segment guard; delete on resolved property) - applyProjection packages/db-connect/lib/shared.js:164-216 (exclusion branch calls unsetNestedField per excluded key) Reachability driver (consumer on a SQL adapter): - project.launder / project.finalize packages/apostrophe/modules/@apostrophecms/doc-type/index.js:2003-2103 - getRestQuery packages/apostrophe/modules/@apostrophecms/piece-type/index.js:1139-1157 - SQLite adapter applyProjection call packages/db-connect/adapters/sqlite.js:906,980 ``` ## Impact Prerequisites: an authenticated account holding `view-draft` (every editing role; any logged-in user when `guestApiAccess: true`), and a consumer configured to use a SQLite, PostgreSQL, or multipostgres adapter. The default `mongodb` adapter hands the projection to the real MongoDB driver and is not affected. With those conditions, a single crafted GET request deletes an attacker-chosen shared prototype method (for example `Object.prototype.hasOwnProperty`, `toString`, or an `Array.prototype` member). The demonstrated capability is a persistent, process-wide denial of service: after the deletion, ordinary calls such as `obj.hasOwnProperty(...)` throw across Apostrophe, its dependencies, and the database driver, so the affected Node process cannot service requests for any user until it is restarted. The attacker chooses which member to remove, and the corruption of shared runtime state persists for the life of the process. ## Proof of Concept `The finding was reproduced by executing the shipped helper directly against the published db-connect source; a live consumer requires a SQLite or PostgreSQL adapter, an authenticated view-draft session, and at least one matching document.` 1. Authenticate as any user with `view-draft` on a site whose database adapter is `sqlite`, `postgres`, or `multipostgres`. 2. Issue a piece-type REST read with an exclusion projection whose key targets a shared prototype method. 3. Observe that subsequent requests fail process-wide because the shared method was deleted. ```text GET /api/v1/@apostrophecms/article?project[constructor.prototype.hasOwnProperty]=0 Cookie: <authenticated view-draft session> ``` ```text safe benign exclusion {title:0} leaves Object.prototype.hasOwnProperty intact VULNERABLE exclusion projection deleted Object.prototype.hasOwnProperty (callableBefore=true, brokeEveryObject=true) VULNERABLE exclusion projection deleted an arbitrary Object.prototype method (__pocMarker) ``` ## Attack Chain 1. **Exposure:** An authenticated `view-draft` user calls the piece-type REST GET endpoint `GET /api/v1/@apostrophecms/<piece-type>`, which is reachable by any editing role. 2. **Control:** The query string `project[constructor.prototype.hasOwnProperty]=0` is parsed by `qs` (with `allowDots` off) into a single own key with literal dots, `{ 'constructor.prototype.hasOwnProperty': '0' }`. 3. **Path:** `getRestQuery` applies the query builders first; `project.launder` copies the key verbatim and coerces only the value to `false`; `project.finalize` skips the falsy value with `if (!val) continue` and preserves the key; the cursor stores it as the projection. 4. **Guard:** The `publicApiProjection` override that would discard the attacker projection runs only when `canAccessApi(req)` is false, so it is skipped for the authenticated caller; no key allowlist, segment check, or prototype guard exists anywhere on the path. 5. **Primitive:** On the SQLite or PostgreSQL adapter, `applyProjection` takes the exclusion branch and calls `unsetNestedField(result, 'constructor.prototype.hasOwnProperty')`, which resolves `Object.prototype` and executes `delete Object.prototype.hasOwnProperty`. 6. **Result:** A shared prototype method is removed for the entire Node process, so request handling throws for all users and tenants until restart. ## Bypass Evidence The relevant protections were examined individually and none blocks this path. The projection `launder` (packages/apostrophe/modules/@apostrophecms/doc-type/index.js:2003-2011) laundens values only and retains arbitrary keys. The `publicApiProjection` permission override (packages/apostrophe/modules/@apostrophecms/piece-type/index.js:1142-1156) is gated on `!canAccessApi(req)` and is therefore not taken for an authenticated `view-draft` caller. The `finalize` per-key loop (doc-type/index.js:2062-2069) short-circuits on the falsy exclusion value before it ever inspects the key. Most importantly, `unsetNestedField` (packages/db-connect/lib/shared.js:119-129) has no segment guard at all: its sibling `setNestedField` blocks a literal `__proto__` but neither helper blocks `constructor` or `prototype`, and the `constructor.prototype.<member>` path bypasses even that partial `__proto__` check. Attempts to disprove the finding all failed: routing the value to the inclusion branch (which uses `setNestedField`) does not occur because the value is falsy; the working object is a plain object from `JSON.parse(JSON.stringify(doc))` so its `constructor` is the global `Object`; and `Object.prototype.hasOwnProperty` is configurable, so the delete succeeds. The seed prototype-pollution fix added a `{__proto__, constructor, prototype}` segment guard, but only in `apos.util.set`/`get` in the separate `apostrophe` package; the db-connect helpers were never hardened. ## Affected Versions - `Ecosystem: npm` - `Package: @apostrophecms/db-connect` - `Confirmed affected range: >= 1.0.0, <= 1.0.2` - `Latest release checked: 1.0.2 (npm registry)` - `Fix status: not fixed` The unguarded `unsetNestedField` and the exclusion-branch `applyProjection` call are byte-identical across the published stable releases 1.0.0, 1.0.1, and 1.0.2, and the SQLite and PostgreSQL adapters invoke `applyProjection` per returned document in all of them. No published release fixes the issue. The prerelease line (1.0.0-alpha.1, 1.0.0-alpha.2, 1.0.2-alpha.0) ships the same code but is outside the supported stable channel. Reachability requires a consumer on a SQLite, PostgreSQL, or multipostgres adapter; the default `mongodb` adapter delegates the projection to the real MongoDB driver and is not affected. The `apostrophe` package, which drives reachability, declares `@apostrophecms/db-connect@^1.0.1`, resolving to the affected 1.0.2. ## Suggested Fix Enforce that untrusted field paths can never traverse into shared prototype objects. Both `unsetNestedField` and `setNestedField` in `packages/db-connect/lib/shared.js` should reject any path whose segments include `__proto__`, `constructor`, or `prototype`, mirroring the `unsafePathSegments` guard already used in the `apostrophe` package's `apos.util.set`/`get`; equivalently, the helpers can traverse own-properties only (for example using `Object.prototype.hasOwnProperty` checks captured before use, or `Map`-based access) so that resolution cannot reach prototype objects. Because `applyProjection` is the reachable gate, adding the guard at the helper level protects every adapter path at once. As an interim mitigation without a code change, deployments can run on the default `mongodb` adapter (which is not affected) or restrict authenticated API access so that only fully trusted roles can reach the piece-type REST endpoints. Reported by zx (GitHub: @manus-pi).

Source published

20 Oct 2026 18:03:50 UTC

Source modified

20 Oct 2026 18:15:04 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

Publisher rating · HIGH