How severe is GHSA-6c87-g9pw-78fx?

GHSA-6c87-g9pw-78fx has a CVSS score of 3.7/10, rated LOW. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-6c87-g9pw-78fx?

GHSA-6c87-g9pw-78fx affects the following packages: github.com/edgelesssys/contrast (Go). Ecosystems affected: Go.

How do I fix GHSA-6c87-g9pw-78fx?

Update github.com/edgelesssys/contrast to 1.21.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6c87-g9pw-78fx is resolved across your whole dependency graph.

How do I detect GHSA-6c87-g9pw-78fx in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/edgelesssys/contrast. 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 GHSA-6c87-g9pw-78fx 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 GHSA-6c87-g9pw-78fx?

O3 pinpoints whether GHSA-6c87-g9pw-78fx 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 GHSA-6c87-g9pw-78fx actively exploited in the wild?

No public exploit code has been indexed for GHSA-6c87-g9pw-78fx 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.

When was GHSA-6c87-g9pw-78fx published, and has it been updated?

GHSA-6c87-g9pw-78fx was published on July 1, 2026 and was last updated on July 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

GHSA-6c87-g9pw-78fx

LOW

Contrast's Imagepuller registryFor uses unanchored suffix matching, leaking auth credentials and trusted CA configuration to sibling-domain registries

Also known asGO-2026-5865

Published

Jul 1, 2026

Updated

Jul 7, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

1 pkg affected

🐹github.com/edgelesssys/contrast

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Summary

Config.registryFor selected a per-registry credential / CA / mirror block by checking strings.HasSuffix(name, fqdn) after stripping a single trailing dot. The match has no boundary between the configured FQDN and any preceding characters in the request hostname. A registry configured as [registries."ghcr.io."] is therefore also applied to any image pulled from a host whose name happens to end in the literal byte sequence ghcr.io, including attacker-registered domains such as evilghcr.io. The imagepuller would then send the configured Authorization header (basic auth, registry token, or identity token), trust the configured custom CA bundle, follow the configured mirror, or honour insecure-skip-verify, on requests to that hostname.

Prerequisites

For this to be applicable, an image or layer must be pulled from a "sibling" domain ending in one of the FQDNs configured in the imagepuller config. This may occur due to malicious intent or coincidentally.

Impact

Authentication header leaks to the sibling registry.
If insecure-skip-verify is set on an FQDN, TLS will also not be verified for the sibling registry.
Mirrors configured for an FQDN will also be used with the sibling registry.

Not impacted

Image integrity is not impacted. Image bytes remain pinned by digest in the policy and are validated after the pull. This advisory does not allow code substitution.

Workaround

If possible, configure explicit subdomains in the imagepuller config. A configuration for [registries.".example.registry"] is unaffected, only [registries."example.registry"] is potentially affected.
Audit images and layers configured in the deployment for the existence of sibling domains.

Patches

After this patch, registry matches are determined by exact label equality instead of suffix matching. Each .-separated part of the FQDN must be an exact match with the corresponding label in the image reference.

Severity

AV:N because the leak is over the network to a registry under the attacker's control.
AC:H because exploitation requires the operator to have configured a registry FQDN without a leading . AND the attacker to control a sibling-suffix domain that the deployment will pull from.
PR:N for the eventual recipient.
S:U because impact stays in the imagepuller.
C:L for credential leak (no integrity / availability impact).

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/edgelesssys/contrast`	all versions	1.21.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/edgelesssys/contrast. 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 github.com/edgelesssys/contrast to 1.21.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6c87-g9pw-78fx 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 GHSA-6c87-g9pw-78fx 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 GHSA-6c87-g9pw-78fx. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

# Summary `Config.registryFor` selected a per-registry credential / CA / mirror block by checking `strings.HasSuffix(name, fqdn)` after stripping a single trailing dot. The match has no boundary between the configured FQDN and any preceding characters in the request hostname. A registry configured as `[registries."ghcr.io."]` is therefore also applied to any image pulled from a host whose name happens to end in the literal byte sequence `ghcr.io`, including attacker-registered domains such as `evilghcr.io.` The imagepuller would then send the configured `Authorization` header (basic auth,

O3 Security · Impact-Aware SCA

Is GHSA-6c87-g9pw-78fx in your dependencies?

O3 detects GHSA-6c87-g9pw-78fx across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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