GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

GHSA-2R2P-4CGF-HV7H

Vulnerability from github – Published: 2026-04-22 14:52 – Updated: 2026-04-22 14:52
VLAI
Summary
engram: HTTP server CORS wildcard + auth-off-by-default enables CSRF graph exfiltration and persistent indirect prompt injection
Details

Summary

The local HTTP server started by engram server (binding 127.0.0.1:7337 by default) was exposed to any browser origin with no authentication unless ENGRAM_API_TOKEN was explicitly set. Combined with Access-Control-Allow-Origin: * on every response and a body parser that did not require Content-Type: application/json, this allowed a malicious web page the developer visited to:

  1. Exfiltrate the local knowledge graph via GET /query and GET /stats (function names, file layout, recorded decisions/mistakes).
  2. Inject persistent prompt-injection payloads via POST /learn, which wrote mistake/decision nodes that were later surfaced as system-reminders to the user's AI coding agent on every future session and file edit.

Severity: High — confidentiality + persistent indirect prompt injection against the user's coding agent.

Affected versions

engramx >= 1.0.0, < 2.0.2 — any version that shipped the HTTP server.

Patched in

engramx@2.0.2

Workarounds (if you cannot upgrade)

  • Do not run engram server or engram ui.
  • If developers must, set ENGRAM_API_TOKEN to a long random value and terminate the server before browsing the web.

Remediation (applied in 2.0.2)

  1. Fail-closed auth on every non-public route — Bearer header or HttpOnly cookie, constant-time comparison, 256-bit auto-generated token at ~/.engram/http-server.token (0600).
  2. Wildcard CORS removed entirely; default is no CORS headers. Opt-in allowlist via ENGRAM_ALLOWED_ORIGINS.
  3. Host + Origin validation — rejects DNS rebinding and Host spoofing.
  4. Content-Type: application/json enforced on mutations — blocks the text/plain CSRF vector.
  5. /ui?token= bootstrap with Sec-Fetch-Site gate — prevents cross-origin oracle probing.

Credit

Discovered and responsibly disclosed by @gabiudrescu in engram issue #7.

Severity
8.6 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "engramx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-1188",
      "CWE-306",
      "CWE-352",
      "CWE-942"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-22T14:52:03Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\nThe local HTTP server started by `engram server` (binding `127.0.0.1:7337` by default) was exposed to any browser origin with no authentication unless `ENGRAM_API_TOKEN` was explicitly set. Combined with `Access-Control-Allow-Origin: *` on every response and a body parser that did not require `Content-Type: application/json`, this allowed a malicious web page the developer visited to:\n\n1. **Exfiltrate** the local knowledge graph via `GET /query` and `GET /stats` (function names, file layout, recorded decisions/mistakes).\n2. **Inject persistent prompt-injection payloads** via `POST /learn`, which wrote `mistake`/`decision` nodes that were later surfaced as system-reminders to the user\u0027s AI coding agent on every future session and file edit.\n\nSeverity: **High** \u2014 confidentiality + persistent indirect prompt injection against the user\u0027s coding agent.\n\n### Affected versions\n\n`engramx` \u003e= 1.0.0, \u003c 2.0.2 \u2014 any version that shipped the HTTP server.\n\n### Patched in\n\n`engramx@2.0.2`\n\n### Workarounds (if you cannot upgrade)\n\n- Do **not** run `engram server` or `engram ui`.\n- If developers must, set `ENGRAM_API_TOKEN` to a long random value and terminate the server before browsing the web.\n\n### Remediation (applied in 2.0.2)\n\n1. Fail-closed auth on every non-public route \u2014 Bearer header or HttpOnly cookie, constant-time comparison, 256-bit auto-generated token at `~/.engram/http-server.token` (0600).\n2. Wildcard CORS removed entirely; default is no CORS headers. Opt-in allowlist via `ENGRAM_ALLOWED_ORIGINS`.\n3. Host + Origin validation \u2014 rejects DNS rebinding and Host spoofing.\n4. `Content-Type: application/json` enforced on mutations \u2014 blocks the text/plain CSRF vector.\n5. `/ui?token=` bootstrap with `Sec-Fetch-Site` gate \u2014 prevents cross-origin oracle probing.\n\n### Credit\n\nDiscovered and responsibly disclosed by @gabiudrescu in engram issue #7.",
  "id": "GHSA-2r2p-4cgf-hv7h",
  "modified": "2026-04-22T14:52:03Z",
  "published": "2026-04-22T14:52:03Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/NickCirv/engram/security/advisories/GHSA-2r2p-4cgf-hv7h"
    },
    {
      "type": "WEB",
      "url": "https://github.com/NickCirv/engram/issues/7"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/NickCirv/engram"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "engram: HTTP server CORS wildcard + auth-off-by-default enables CSRF graph exfiltration and persistent indirect prompt injection"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.