Medium · CVSS 5.3CVE-2026-105770

Octo STS discloses trust policy contents to unauthorized callers via Exchange error messagesCVE-2026-105770

Answer in brief

CVE-2026-105770 records a Medium severity (CVSS 5.3) vulnerability in Octo STS discloses trust policy contents to unauthorized callers via Exchange error messages. The current sources do not mark it as known exploited. The current feed maps octo-sts/github.com/octo-sts/app (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 Nov 3, 2026Updated Nov 3, 2026Source checked Nov 3, 2026First seen by HOL Nov 3, 2026Material review Nov 3, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.3
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 5.3. 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 octo-sts/github.com/octo-sts/app (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
octo-sts/github.com/octo-sts/appgeneric	>=0 <0.11.2	0.11.2

Recommended response

Check inventory. Check lockfiles and deployed manifests for octo-sts/github.com/octo-sts/app.
Review the reported fix. Source-reported solution: Upgrade to Octo STS 0.11.2 or later. The token is now checked against the trust policy immediately after the policy is loaded and before installation selection or app pin resolution. On a mismatch the detailed reason is logged and recorded on the operator audit event, and the caller receives only a generic "PermissionDenied: token does not match trust policy". Policies that exist but cannot be read, parsed or compiled now return the same NotFound response as a missing policy. Users of the hosted service are protected once the fix is deployed.

Evidence timeline and material changes

Published upstream
Nov 3, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Nov 3, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Nov 3, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.

Package

Affected range

Fixed version

octo-sts/github.com/octo-sts/appgeneric

>=0 <0.11.2

0.11.2

Recommended response

Check inventory. Check lockfiles and deployed manifests for octo-sts/github.com/octo-sts/app.

Review the reported fix. Source-reported solution: Upgrade to Octo STS 0.11.2 or later. The token is now checked against the trust policy immediately after the policy is loaded and before installation selection or app pin resolution. On a mismatch the detailed reason is logged and recorded on the operator audit event, and the caller receives only a generic "PermissionDenied: token does not match trust policy". Policies that exist but cannot be read, parsed or compiled now return the same NotFound response as a missing policy. Users of the hosted service are protected once the fix is deployed.

Sources and claim methodology

Upstream source description

Quoted source text, attributed separately from HOL analysis.