How severe is CVE-2026-57495?

No CVSS score has been assigned to CVE-2026-57495 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-57495?

CVE-2026-57495 affects the following packages: @agenticmail/core (npm), @agenticmail/claudecode (npm), @agenticmail/codex (npm), @agenticmail/openclaw (npm). Ecosystems affected: npm.

How do I fix CVE-2026-57495?

Update @agenticmail/core to 0.9.43 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-57495 is resolved across your whole dependency graph.

How do I detect CVE-2026-57495 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @agenticmail/core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-57495 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-57495?

O3 pinpoints whether CVE-2026-57495 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-57495 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-57495 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-57495?

CVE-2026-57495 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 29th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-57495?

CVE-2026-57495 is classified as Missing Authentication (CWE-306). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-57495 published, and has it been updated?

CVE-2026-57495 was published on June 18, 2026 and was last updated on July 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-57495

CVE-2026-57495 is a Missing Authentication vulnerability in @agenticmail/core. O3 Security confirms whether CVE-2026-57495 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

AgenticMail: Unauthenticated inbound mail triggers bypassPermissions resume of the operator's Claude Code session (bridge-wake)

Published

Jun 18, 2026

Updated

Jul 21, 2026

Affected

4 pkgs

Patched

4 / 4

Exploits

None indexed

Exploitation data as of Sep 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-57495.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk+0.08%

Lower risk than most CVEs29th percentile — riskier than 29% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

4 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

6other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@agenticmail/corenpm

218downloads / week

@agenticmail/claudecodenpm

98downloads / week

@agenticmail/codexnpm

70downloads / week

Description

Summary

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:2040 handleBridgeMail extracts subject/from/preview (:2045-2049) and calls planBridgeWake({ 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:141 composeBridgeWakePrompt embeds the untrusted from/subject/preview (preview sliced to 600 chars at :144) verbatim into the prompt.
packages/claudecode/src/bridge-wake.ts:103 resumeBridgeSession runs the prompt via the Claude Code SDK with permissionMode: '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.

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.

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.

Suggested fix

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).

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.

Affected Packages

4 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@agenticmail/core`	all versions	0.9.43
📦npm	`@agenticmail/claudecode`	all versions	0.2.39
📦npm	`@agenticmail/codex`	all versions	0.1.33
📦npm	`@agenticmail/openclaw`	all versions	0.5.71

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @agenticmail/core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @agenticmail/core to 0.9.43 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-57495 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-57495 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-57495. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary 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 OAu

O3 Security · Impact-Aware SCA

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