Logto: SSRF via Webhooks and Custom OAuth2 Connector UserInfo Endpoint (CVE-2026-56739) | HOL Guard CVE

High · CVSS 8.5CVE-2026-56739

Logto: SSRF via Webhooks and Custom OAuth2 Connector UserInfo Endpoint

Answer in brief

CVE-2026-56739 records a High severity (CVSS 8.5) vulnerability in Logto: SSRF via Webhooks and Custom OAuth2 Connector UserInfo Endpoint. The current sources do not mark it as known exploited. The current feed maps logto-io/logto (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 24, 2026Updated Sep 24, 2026Source checked Sep 25, 2026First seen by HOL Sep 25, 2026Material review Sep 24, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.5
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps logto-io/logto (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
logto-io/logtogeneric	<1.43.0	1.43.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for logto-io/logto.
Review the reported fix. Update logto-io/logto to 1.43.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 25, 2026

Sources and claim methodology

Upstream source description

Logto is the modern, open-source auth infrastructure for SaaS and AI apps. Prior to 1.43.0, Logto fetches administrator-controlled outbound destinations without validating the address used for the connection. Webhook delivery in packages/core/src/libraries/hook/utils.ts can reach special-use and cloud metadata addresses. Custom OAuth2 connectors can use an attacker-selected userInfoEndpoint and forward the OAuth access token in the Authorization header, while OIDC connectors can fetch an attacker-selected jwksUri. The affected operations require tenant administrative configuration access, but they cross the server's network boundary and can expose internal data or upstream provider credentials. This issue is fixed in version 1.43.0.

Quoted source text, attributed separately from HOL analysis.