CVE-2026-50027: mcp-memory-service: Missing Authentication on Document API Endpoints Allows Unauthenticated Memory Read/Write/Delete

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 1.0%, percentile 61: FIRST’s model estimates a 1.0% chance of exploitation activity in the next 30 days, higher than 61% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes mcp-memory-service (PyPI) < 10.67.1, fixed in 10.67.1. Check your lockfile, including transitive dependencies.

What it is

mcp-memory-service is a semantic memory layer for AI applications. Prior to 10.67.1, all HTTP routes under /api/documents/ in mcp-memory-service are served without any authentication dependency, even when the server is configured with an API key (MCPAPIKEY) or OAuth. An unauthenticated remote attacker can upload arbitrary content into the memory store (write), retrieve stored document content (read), and permanently delete memories belonging to authenticated users (delete) — all without supplying any credentials. The /api/memories counterpart correctly enforces authentication, making this an inconsistent and exploitable authentication boundary. This vulnerability is fixed in 10.67.1.

From the GitHub advisory

Missing Authentication on Document API Endpoints Allows Unauthenticated Memory Read/Write/Delete

Summary

All HTTP routes under /api/documents/ in mcp-memory-service are served without any authentication dependency, even when the server is configured with an API key (MCPAPIKEY) or OAuth. An unauthenticated remote attacker can upload arbitrary content into the memory store (write), retrieve stored document content (read), and permanently delete memories belonging to authenticated users (delete) — all without supplying any credentials. The /api/memories counterpart correctly enforces authentication, making this an inconsistent and exploitable authentication boundary. CVSS 9.8 Critical.

Details

The documents.py router is instantiated without any router-level dependencies= parameter and the file does not import Depends at all, so no authentication guard is present on any of its routes:

Weakness type: CWE-306.

Product: mcp-memory-service (PyPI) · Assigned by: GitHub_M · Published: 2026-08-14

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.96% probability of exploitation activity in the next 30 days; percentile 61.

Timeline

• 2026-07-02 — GitHub-reviewed advisory GHSA-84hp-mqvj-3p8h published (critical)
• 2026-08-14 — CVE record published by GitHub_M
• 2026-08-17 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-84hp-mqvj-3p8h github.com
2. CVE.org record CVE-2026-50027 cve.org
3. NVD entry CVE-2026-50027 nvd.nist.gov

Other references from the CVE record and advisory

1. web.archive.org web.archive.org
2. pypi.org pypi.org
3. github.com github.com

Critical PyPI advisories · Today’s Security Digest