Summary
AgenticMail: Unauthenticated inbound mail triggers bypassPermissions resume of the operator's Claude Code session (bridge-wake)
Two inbound-mail handlers act on a privileged effect without verifying that the sender is the operator, while a sibling handler in the same repo does. The higher-impact one: any external email routed to the bridge inbox causes the dispatcher to resume the operator's Claude Code session with permissionMode: 'bypassPermissions', embedding the attacker-controlled from/subject/preview verbatim into the prompt the resumed agent reads, an indirect prompt injection into a fully-privileged agent (Bash/Write/Edit/WebFetch + the agenticmail MCP toolbelt) running as the operator's OAuth identity. The sibling operator-query email-reply hook gates the same untrusted-From provenance with isOperatorReplySender(replyFrom, config.operatorEmail) (fail-closed); the bridge-wake path, a strictly higher-privilege effect, has no equivalent.
Affected code (current HEAD, commit b95f52e)
Untrusted provenance: external inbound email enters at packages/api/src/routes/inbound.ts:41 (POST /mail/inbound); the x-inbound-secret authenticates only the relay->API hop, not the external sender, so from/subject/preview are attacker-controlled.
Privileged sink (bridge-wake, bypassPermissions):
packages/claudecode/src/dispatcher.ts:2040handleBridgeMailextractssubject/from/preview(:2045-2049) and callsplanBridgeWake({ session, mail: { ..., from, preview } })(:2052) with NO sender check, routing keys only on session freshness (skip-live / escalate / resume).planBridgeWake->packages/core/src/host-bridge.ts:141composeBridgeWakePromptembeds the untrustedfrom/subject/preview(preview sliced to 600 chars at:144) verbatim into the prompt.packages/claudecode/src/bridge-wake.ts:103resumeBridgeSessionruns the prompt via the Claude Code SDK withpermissionMode: 'bypassPermissions'against the operator's last session (resume + same mcpServers).
Guarded sibling (same class, authenticated): packages/api/src/routes/inbound.ts:102 rejects an operator-query email reply unless isOperatorReplySender(replyFrom, config.operatorEmail) (def packages/core/src/phone/realtime-tools.ts:999, fail-closed when no operatorEmail), with a v0.9.53 security-review comment (inbound.ts:93-100) stating inbound mail provenance is untrusted and an emailed answer is only honored when its From matches the configured operator. The Telegram sibling likewise gates on operatorChatId. The bridge-wake path ignores this exact lesson.
Secondary instance (same root cause): packages/core/src/gateway/manager.ts:261 tryProcessApprovalReply releases a held outbound email on an "approve" reply matched only by In-Reply-To / notification_message_id, with no sender check, again unlike the isOperatorReplySender sibling.
Proof of concept (static / request-difference; dynamic on operator's OWN setup only)
Static: the from/subject/preview extracted at dispatcher.ts:2045-2049 flow into composeBridgeWakePrompt (host-bridge.ts:141) and resumeBridgeSession (bridge-wake.ts:103) with no interposed sender check, while the sibling inbound.ts:102 has one, the same untrusted-From provenance is authenticated on one privileged email path and not on the higher-privileged one. Dynamic (own instance only): with a configured bridge + fresh host-session, send mail from a non-operator address into the bridge inbox whose subject/preview contains a benign instruction writing a fresh CSPRNG marker; observe the resumed bypassPermissions session act on it. Use only your own instance; do not target third-party deployments.
Affected versions
Present on current HEAD (core 0.9.42 / claudecode 0.2.38, commit b95f52e). No fix retrofits the sender check onto bridge-wake.
Severity (honest, both ways)
HIGH, plausibly CRITICAL in a configured headless-bridge deployment. Ceiling ~9.0 (unauthenticated external sender -> operator-privileged code execution). Floor ~7.0: the auth gap is unconditional, but full impact requires (1) a fresh <24h host-session, (2) external mail routed to the bridge inbox, (3) the resumed model obeying injected instructions (non-deterministic). Not a deterministic RCE primitive. CWE-306 (missing authentication for the privileged action) + CWE-77/CWE-94 (injected instructions realized as command execution). Novelty: the two existing agenticmail advisories (CVE-2026-50287 MCP missing-auth; CVE-2026-47255 storage SQL) do not cover this sink. Please rate per your deployment assumptions.
Impact
In a configured headless-bridge deployment (operator uses the CLI so a host-session is saved; session fresh <24h per host-sessions.ts:127; external mail routed to the bridge inbox via relay sub-addressing or a Cloudflare webhook), an external sender achieves indirect prompt injection into a bypassPermissions operator session -> arbitrary OS command execution, filesystem read/write, and exfiltration under the operator's OAuth identity. The auth gap (no sender check on the bridge path) is structural and unconditional; the impact realization is config-conditional and depends on the resumed model following injected instructions.
A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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Mirror the guarded sibling: before any bypassPermissions resume (dispatcher.ts handleBridgeMail, before planBridgeWake), require trusted provenance, an internal sub-agent wake OR isOperatorReplySender(from, config.operatorEmail); otherwise deliver the mail normally but do NOT resume. Reuse the existing exported isOperatorReplySender from @agenticmail/core so the two privileged email paths share one authentication helper. Defense-in-depth: in composeBridgeWakePrompt, wrap the untrusted fields in explicit untrusted-data delimiters and drop bypassPermissions for mail-triggered resumes whose provenance is not the operator. Apply the same sender gate to tryProcessApprovalReply (manager.ts:261).
Frequently Asked Questions
- What is CVE-2026-57495? CVE-2026-57495 is a high-severity missing authentication for critical function vulnerability in @agenticmail/core (npm), affecting versions < 0.9.43. It is fixed in 0.9.43, 0.2.39, 0.1.33, 0.5.71. A critical operation is accessible without requiring any authentication.
- Which packages are affected by CVE-2026-57495?
@agenticmail/core(npm) (versions < 0.9.43)@agenticmail/claudecode(npm) (versions < 0.2.39)@agenticmail/codex(npm) (versions < 0.1.33)@agenticmail/openclaw(npm) (versions < 0.5.71)
- Is there a fix for CVE-2026-57495? Yes. CVE-2026-57495 is fixed in 0.9.43, 0.2.39, 0.1.33, 0.5.71. Upgrade to this version or later.
- Is CVE-2026-57495 exploitable, and should I be worried? Whether CVE-2026-57495 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-57495 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-57495?
- Upgrade
@agenticmail/coreto 0.9.43 or later - Upgrade
@agenticmail/claudecodeto 0.2.39 or later - Upgrade
@agenticmail/codexto 0.1.33 or later - Upgrade
@agenticmail/openclawto 0.5.71 or later
- Upgrade