---
id: "CVE-2026-105770"
kind: "vulnerability"
aliases: ["CVE-2026-105770"]
title: "Octo STS: trust policy rules leak to callers without a matching token"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["github-actions", "octo-sts", "oidc", "package", "self-hosted"]
not_affected_if: ["managed-hosting", "version-0.11.2-or-later"]
published_at: "2026-11-03T01:16:44+00:00"
first_seen_at: "2026-11-03T01:47:23+00:00"
updated_at: "2026-11-03T01:48:24+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-105770", "first_seen_at": "2026-11-03T01:47:23+00:00"}]
---

# Octo STS: trust policy rules leak to callers without a matching token

Octo STS, a GitHub app that exchanges OIDC tokens for GitHub access, returned the issuer, subject, audience and claim rules of a trust policy in error messages to callers the policy does not trust. An attacker with any valid OIDC token, such as one from a repository they own, can read those matching rules, which often name internal repositories, branches, environments or cloud account identifiers, but cannot mint tokens or bypass the policy.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the Octo STS app version deployed for your instance; affected if it is before `0.11.2`
- Review your trust policy files for internal repository names, branch names, environment names or cloud account IDs that would be sensitive if disclosed

## Fix

- Octo STS (github.com/octo-sts/app): move to `0.11.2` or later

## Timeline

- 2026-11-03T01:47:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-105770

## Documents

- [advisory] Vendor advisory: github.com https://github.com/octo-sts/app/security/advisories/GHSA-h5p6-j8m9-xx4p
- [fix] Patch: github.com https://github.com/octo-sts/app/commit/88c6432adc4f497ec69b574e1ce162a564a9e71a
- [fix] Release notes: github.com https://github.com/octo-sts/app/releases/tag/v0.11.2

## From the sources

Octo STS (github.com/octo-sts/app) before 0.11.2 returns trust policy configuration to callers whose OIDC token does not satisfy that policy. TrustPolicy.CheckToken included the policy's issuer, subject and audience values or patterns and claim_pattern names and regular expressions in its PermissionDenied errors, which Exchange returned verbatim. Exchange also selected the GitHub App installation before checking the token, so errors from resolving the policy's app or app_pattern pin were returned to callers the policy does not trust. An attacker who holds any validly signed OIDC token, such as a GitHub Actions token from a repository they own, and who knows or guesses a target owner/repo and identity name can read that policy's matching rules, even when the policy is stored in a private repository. These rules often name internal repositories, branches, environments or cloud account identifiers. The issue does not allow minting tokens or bypassing a trust policy. This issue is fixed in 0.11.2.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_