All vulnerabilities
CVE-2026-56739GHSA-3556-624q-c5w3

Logto: SSRF via Webhooks and Custom OAuth2 Connector UserInfo Endpoint

logto-io logto
CVSS
8.5High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.30%Chance of exploitation activity in the next 30 days, higher than 21% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in1.43.0Fixed versionGitHub
Published24 Sep 2026Updated 28 Sep 2026CVE List

What fixes it

  • 1.43.0@logto/core, npmGitHubnpm install @logto/core@1.43.0

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 2

  • logtoaffected: < 1.43.0CVE List
  • @logto/core, npm<= 1.42.0GitHub

References 4