How severe is CVE-2026-55761?

No CVSS score has been assigned to CVE-2026-55761 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-55761?

Affected package information for CVE-2026-55761 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2026-55761?

No patched version of the affected component has shipped for CVE-2026-55761 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2026-55761 in my code and dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. 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 CVE-2026-55761 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 CVE-2026-55761?

O3 pinpoints whether CVE-2026-55761 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 CVE-2026-55761 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-55761 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.

What type of vulnerability is CVE-2026-55761?

CVE-2026-55761 is classified as Improper Authentication (CWE-287). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-55761 published, and has it been updated?

CVE-2026-55761 was published on July 8, 2026 and was last updated on July 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-55761: vulnerability details, affected versions & fix

Description

Portainer Community Edition is a lightweight service delivery platform for containerized applications that can be used to manage Docker, Swarm, Kubernetes and ACI environments. In versions 2.39.0 through 2.39.3 and 2.40.0 until 2.43.0, unauthenticated restore and administrator initialization endpoints (/api/restore and /api/users/admin/init) remain accessible during the five-minute setup window for uninitialized instances, allowing a network attacker to restore a crafted backup or create the first administrator account and gain full administrative access. This issue is fixed in versions 2.39.4 and 2.43.0.

Detection & mitigation playbook

Vulnerability

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. 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.
Remediation status
No patched version of the affected component has shipped for CVE-2026-55761 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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 CVE-2026-55761 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 CVE-2026-55761. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Portainer Community Edition is a lightweight service delivery platform for containerized applications that can be used to manage Docker, Swarm, Kubernetes and ACI environments. In versions 2.39.0 through 2.39.3 and 2.40.0 until 2.43.0, unauthenticated restore and administrator initialization endpoints (/api/restore and /api/users/admin/init) remain accessible during the five-minute setup window for uninitialized instances, allowing a network attacker to restore a crafted backup or create the first administrator account and gain full administrative access. This issue is fixed in versions 2.39.4

O3 Security · Impact-Aware SCA

Is CVE-2026-55761 in your dependencies?

O3 detects CVE-2026-55761 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2026-55761

Description

Detection & mitigation playbook

Detect

Remediation status

Mitigate without a patch

How O3 protects you

Frequently Asked Questions

Is CVE-2026-55761 in your dependencies?