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Atomicorp WAF Research Note: CVE-2026-44881

CVE Details

Status: Attack Blocked by Atomicorp
Technical CPE data

This section lists vulnerable CPE matches retained from the NVD configurations. It supplements the readable affected-product information above.

  • cpe:2.3:a:portainer:portainer:*:*:*:*:community:*:*:*
    • Version start (inclusive): 2.33.0
    • Version end (exclusive): 2.33.8
    • NVD match criteria ID: 4E7FE81D-D489-4034-9DB4-D48E3B6C3CE4
  • cpe:2.3:a:portainer:portainer:*:*:*:*:community:*:*:*
    • Version start (inclusive): 2.34.0
    • Version end (exclusive): 2.39.2
    • NVD match criteria ID: 42BB76C6-ADCE-4D73-BAF0-7DBBB707C360
  • cpe:2.3:a:portainer:portainer:2.40.0:*:*:*:community:*:*:*
    • NVD match criteria ID: 69F71AFC-F50D-4D10-9918-413D8E841CC2

Vulnerability 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. From 2.33.0 to before 2.33.8, 2.39.2, and 2.41.0, Portainer supports deploying stacks from Git repositories. When a Git-backed stack is created or updated, Portainer clones the repository using go-git v5, which translates Git blob entries with mode 0o120000 (symlink) into real OS symlinks on the host filesystem via os.Symlink. The only entry blocked from becoming a symlink is .gitmodules; every other path is created as a symlink without validation. Portainer’s GET /api/stacks/{id}/file endpoint then reads the stack entry point with os.ReadFile, which follows OS symlinks transparently. A repository containing docker-compose.yml as a symlink to an arbitrary filesystem path causes the symlink target’s contents to be returned verbatim in the HTTP response. Any authenticated user with rights to create or update a Git-backed stack — the default configuration in Portainer CE — can read arbitrary files accessible to the Portainer process. This vulnerability is fixed in 2.33.8, 2.39.2, and 2.41.0.

  1. Maintain the observed Atomicorp protections. Keep your Atomicorp commercial rules current and confirm that the selected observed rules (340007 , 344360 , 347009 , 390709 ) have not been locally disabled. Atomicorp commercial rules are enabled by default. If you use Atomic WAF, review the applicable policy and rule settings.

  2. Apply the vendor’s remediation. WAF protection is defense in depth and does not replace upgrading or following the affected vendor’s guidance.

    • Affected versions: portainer version >= 2.33.0, < 2.33.8.
    • Affected versions: portainer version >= 2.39.0, < 2.39.2.
    • Affected versions: portainer version >= 2.40.0, < 2.41.0.
    • No specific CNA/vendor solution or workaround is included in the current CVE Record . Review the vendor’s security advisories and supported-release guidance before making changes.

  3. Validate after changes. Confirm rule updates are current, review WAF events for the affected application, and test application behavior after vendor upgrades, mitigations, or local policy changes.

Research Notes

Atomicorp WAF protections are designed around attack techniques and exploit behaviors, allowing existing protections to apply across multiple vulnerabilities without requiring a unique rule for every CVE.

Public Vulnerability References

Test or Research Source

  • Source: Atomicorp AI Research Framework
  • Tags: cve, derived, traversal, waf-probe

Research Note Context

This research note documents exploit-technique analysis associated with this vulnerability and references Atomicorp WAF protections observed during engineering review, testing, or validation activities.

Atomicorp security controls are generally designed to identify and mitigate attack techniques and exploit behaviors rather than individual CVE identifiers. As a result, protections developed for one vulnerability may also apply to related attack variants and future vulnerabilities using similar techniques.

Learn More

Atomicorp develops commercially supported security technologies for web applications, servers, endpoints, workloads, and legacy enterprise platforms.

Organizations interested in protecting systems against exploit techniques associated with vulnerabilities such as this one can learn more about:

  • Atomic ModSecurity Rules: commercially maintained WAF rules for ModSecurity deployments, including protections for web attacks, bots, scanners, malware, exploitation attempts, and emerging vulnerability classes.
  • Atomic WAF: an enterprise web application firewall with Atomicorp rules, centralized management, reporting, authentication controls, and operational tooling.
  • Atomic ModSecurity Integrator: a special licensing option for MSPs, MSSPs, OEMs, VARs, reverse proxy providers, and other integrators who want to incorporate Atomicorp ModSecurity rule technology into their own products or services.
  • Atomic OSSEC: an enterprise OSSEC-based intrusion detection, compliance, and security monitoring platform.
  • Atomic Protector: workload protection for Linux, web, cloud, data center, and hybrid environments.

For additional information, product evaluations, or technical discussions, visit https://www.atomicorp.com/ or https://modsecurity.io/ .