GHSA-5324-3w58-qpp2

Suggest an improvement
Source
https://github.com/advisories/GHSA-5324-3w58-qpp2
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-5324-3w58-qpp2/GHSA-5324-3w58-qpp2.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-5324-3w58-qpp2
Aliases
Published
2026-10-28T21:17:08Z
Modified
2026-10-28T21:30:05Z
Severity
  • 6.3 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
Summary
Mem0: Cross-tenant conversation leak via unescaped delimiter collision in session-scope key (_build_session_scope)
Details

Summary

_build_session_scope() in mem0/memory/main.py builds the conversation-history scope key used to fetch/store the last N raw messages by naively joining caller-supplied user_id/agent_id/run_id values with unescaped & and = delimiters:

def _build_session_scope(filters): parts = [] for key in sorted(["user_id", "agent_id", "run_id"]): val = filters.get(key) if val: parts.append(f"{key}={val}") return "&".join(parts)

_validate_and_trim_entity_id() (the only validation applied to these values) rejects only empty/whitespace-only strings — it never forbids & or =. This scope string is then used as an exact-match key against a SQLite column (storage.py: WHERE session_scope = ?) to fetch the last 10 raw messages for a given scope (main.py, Phase 0 of _add_to_vector_store, both sync and async).

Impact

Any caller who controls only their own run_id (or agent_id) — a very common integration shape, since apps frequently pass a client-/session-supplied identifier straight through as run_id without namespacing — can craft a value containing &user_id= (or &agent_id=) that produces a scope string byte-for-byte identical to a different tenant's real scope string.

Concretely: Tenant A calls add(msgs, user_id="alice", run_id="proj-x") → scope "run_id=proj-x&user_id=alice". An attacker who can only set run_id calls add(msgs, run_id="proj-x&user_id=alice") → identical scope string. The attacker's next add() call:

  1. Reads Tenant A's raw prior conversation via get_last_messages(session_scope) and splices it verbatim into the attacker's own LLM fact-extraction prompt — a direct cross-tenant confidentiality leak (conversation content, potentially including PII, credentials, etc.).
  2. Writes into the same colliding row-set via save_messages(), whose eviction logic (DELETE FROM messages WHERE session_scope = ? AND id NOT IN (...)) can evict/interleave Tenant A's history — permanent cross-tenant data corruption, not just a read.

Reachable via the public Memory.add() / AsyncMemory.add() API, and by extension the REST server's POST /memories endpoint (which takes run_id/agent_id straight from the request body).

Reproduction

from mem0.memory.main import _build_session_scope

Tenant A: real user_id + run_id

scope_a = _build_session_scope({"user_id": "alice", "run_id": "proj-x"}) print(scope_a) # "run_id=proj-x&user_id=alice"

Attacker: controls only run_id, embeds a fake user_id inside it

scope_c = _build_session_scope({"run_id": "proj-x&user_id=alice"}) print(scope_c) # "run_id=proj-x&user_id=alice"

assert scope_a == scope_c # byte-for-byte collision

A full end-to-end proof (actual add() calls, no mocking of the vulnerable functions) confirms the attacker's subsequent add() call receives the victim's raw prior message content via get_last_messages.

Suggested Fix

Reject & and = in _validate_and_trim_entity_id(), alongside the existing whitespace check — this is the single validation chokepoint already used by every entry point (add, search, get_all, delete_all), so the fix is centralized. Alternatively/additionally, encode each component unambiguously (percent-encode each id, or use a length-prefixed/JSON-encoded scope key) so no valid-character combination in one field can ever collide with a different partition.

Also affected: TypeScript SDK (npm mem0ai)

The same flaw exists in mem0-ts/src/oss/src/memory/index.ts, Memory.buildSessionScope(), which joins agent_id/run_id/user_id into the same key=value&key=value string with the delimiters unescaped:

private buildSessionScope(filters: SearchFilters): string { const parts: string[] = []; for (const key of ["agent_id", "run_id", "user_id"].sort()) { const val = (filters as any)[key]; if (val) parts.push(${key}=${val}); } return parts.join("&"); }

The scope string is used the same way, as an exact-match key into the messages table via SQLiteManager.getLastMessages() and saveMessages(), so the identical forge, cross-tenant read and eviction all apply.

Verified against the current releases as of 2026-07-26: pip mem0ai v2.0.14 and npm mem0ai ts-v3.1.2 both still contain the unescaped join.

Reporter: Abhinav Singh (GitHub: OfficialAbhinavSingh)

Database specific 
{
    "cwe_ids":  [
        "CWE-200",
        "CWE-863"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-10-28T21:17:08Z",
    "nvd_published_at":  "2026-10-26T21:18:13Z",
    "severity":  "MODERATE"
}
References

Affected packages

PyPI / mem0ai

Package

Name
mem0ai
View open source insights on deps.dev
Purl
pkg:pypi/mem0ai

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.0.18

Affected versions

0.*
0.0.1
0.0.2
0.0.3
0.0.4
0.0.5
0.0.6
0.0.7
0.0.8
0.0.9
0.0.10
0.0.11
0.0.12
0.0.13
0.0.14
0.0.15
0.0.16
0.0.17
0.0.18
0.0.19
0.0.20rc1
0.0.20
0.0.21
0.1.0
0.1.1
0.1.2
0.1.3
0.1.4
0.1.5
0.1.6
0.1.7
0.1.8
0.1.9
0.1.10
0.1.11
0.1.12
0.1.13
0.1.14
0.1.15
0.1.16
0.1.17
0.1.18
0.1.19
0.1.20a0
0.1.20
0.1.21
0.1.22
0.1.23
0.1.24
0.1.25
0.1.26
0.1.27
0.1.28
0.1.29
0.1.30
0.1.31
0.1.32
0.1.33
0.1.34
0.1.35
0.1.36
0.1.37
0.1.38
0.1.39
0.1.40
0.1.41
0.1.42
0.1.43
0.1.44
0.1.45rc1
0.1.45
0.1.46
0.1.47
0.1.48
0.1.49
0.1.50
0.1.52
0.1.53
0.1.54
0.1.55
0.1.56
0.1.57
0.1.58
0.1.59
0.1.60
0.1.61
0.1.62
0.1.63
0.1.65
0.1.66
0.1.67
0.1.69
0.1.70
0.1.71
0.1.72
0.1.73
0.1.74
0.1.75
0.1.76
0.1.77
0.1.78a0
0.1.78a1
0.1.78a2
0.1.78
0.1.79
0.1.80
0.1.81a0
0.1.81a1
0.1.81a2
0.1.81
0.1.82
0.1.83
0.1.84a1
0.1.84
0.1.85
0.1.86
0.1.87
0.1.88
0.1.89
0.1.90
0.1.91
0.1.92
0.1.93
0.1.94
0.1.95
0.1.96rc1
0.1.96
0.1.97
0.1.98
0.1.99a0
0.1.99a1
0.1.99a2
0.1.99a3
0.1.99
0.1.100
0.1.101
0.1.102
0.1.103
0.1.104
0.1.106
0.1.107rc1
0.1.107rc2
0.1.107
0.1.108
0.1.109
0.1.110
0.1.111
0.1.112
0.1.113
0.1.114
0.1.115
0.1.116
0.1.117
0.1.118
1.*
1.0.0b0
1.0.0
1.0.1
1.0.2
1.0.3
1.0.4
1.0.5
1.0.6
1.0.7
1.0.8
1.0.9
1.0.10
1.0.11
2.*
2.0.0b0
2.0.0b1
2.0.0b2
2.0.0
2.0.1
2.0.2
2.0.3
2.0.4
2.0.5
2.0.6
2.0.7
2.0.8
2.0.10
2.0.11
2.0.12
2.0.13
2.0.14
2.0.15
2.0.16
2.0.17

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-5324-3w58-qpp2/GHSA-5324-3w58-qpp2.json"

npm / mem0ai

Package

Name
mem0ai
View open source insights on deps.dev
Purl
pkg:npm/mem0ai

Affected ranges

Type
SEMVER
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.1.6

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-5324-3w58-qpp2/GHSA-5324-3w58-qpp2.json"