CVE-2026-105407

Executive Summary

CVE-2026-105407 is an OS Command Injection vulnerability (CWE-78) affecting Tuleap Enterprise Edition versions 17.0 through 17.5. An authenticated attacker with low privileges can inject and execute arbitrary operating system commands on the underlying server, achieving full compromise of confidentiality, integrity, and availability. With a CVSS 3.1 base score of 8.8 and no patch currently available, this represents a high-severity risk for organizations running the affected versions in internet-exposed or internally accessible deployments.

Technical Analysis

Tuleap is an open-source application lifecycle management (ALM) and collaboration platform used for software project management, requirements tracking, test management, and DevOps workflows. It is commonly deployed on Linux servers, often internet-facing to support distributed development teams and external collaborators.

The vulnerability class here is OS Command Injection (CWE-78). This class occurs when an application passes externally influenced input to a system shell or command execution function without adequate neutralization of shell metacharacters. The NVD description confirms the flaw affects Tuleap Enterprise Edition from version 17.0 through 17.5, and that successful exploitation allows arbitrary command execution on the server.

Per the CWE-78 definition, the underlying mechanism is that user-controllable input reaches an OS command execution context. This typically manifests where application functionality invokes system utilities (for example, for file processing, report generation, integration with external tools, or administrative operations) and concatenates or interpolates user-supplied values into the command string. Shell metacharacters such as ;, |, &&, `, $(...), and newline characters then permit the attacker to break out of the intended command and execute an arbitrary secondary command with the privileges of the application process (typically the Tuleap web service account).

The CVSS vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H provides important technical constraints:

• AV:N (Network) — the attack is launched remotely over the network; no local access required.
• AC:L (Low) — no special conditions or race windows; exploitation is repeatable and straightforward once the vulnerable path is reached.
• PR:L (Low) — the attacker must hold some valid low-privileged account on the Tuleap instance. This is a significant constraint: unauthenticated internet users cannot exploit directly, but any registered user (including a self-registered or minimally privileged account) can.
• UI:N (None) — no victim interaction is required.
• S:U (Unchanged) — the vulnerable component and impacted component are the same; the CVSS scope is not expanded, but the impact to C/I/A within the server context is High across all three metrics.

The High Confidentiality, Integrity, and Availability impacts reflect that arbitrary command execution as the Tuleap service account grants read access to application data, configuration files, database credentials, and potentially SSH keys or secrets stored on the host; write access to application code, data, and the filesystem; and the ability to terminate processes or disrupt the service (availability). Because the service account may also have outbound network access, the host can be leveraged as a pivot point into the internal network.

The precise vulnerable endpoint, parameter, and the specific system command being invoked are not disclosed in the available NVD description or CNA title. No public proof-of-concept, Nuclei template, or exploit code is known to exist as of this report. Any claim about which specific Tuleap feature (e.g., a particular plugin, import routine, or integration) triggers the flaw would be speculative and is therefore not asserted here. Analysts should treat the entire Tuleap web application surface — especially any feature that shells out to external binaries — as suspect pending vendor clarification.

Exploitation Scenarios

Note: No public PoC is available; the attack chain below is inferred from the vulnerability class (OS Command Injection) and the CVSS characteristics. No specific function names, endpoints, or parameters are asserted because they are not present in the source data.

1. Reconnaissance / Target Identification. The attacker identifies internet-facing or internally reachable Tuleap Enterprise Edition instances. Fingerprinting is straightforward: Tuleap serves distinctive web content and branding, and version disclosure may be possible via application pages or response headers. Shodan queries such as http.title:"Tuleap" or http.html:"Tuleap" can enumerate candidate targets at scale. The attacker then determines whether self-registration is enabled or whether any low-privileged account can be obtained (project member, reporter, or similar).

2. Authentication and Positioning (PR:L). Because the vector requires Low privileges, the attacker either registers an account (if open registration is enabled) or obtains credentials for a minimally privileged user via phishing, credential stuffing, or reuse. The attacker authenticates to the Tuleap web interface. No administrative rights are needed.

3. Triggering the Command Injection. The attacker locates the feature that passes user-controlled input into an OS command context. Since the vulnerable code path is not publicly documented, the attacker would fuzz authenticated functionality — particularly any feature that invokes server-side utilities (imports, exports, report/artifact generation, or third-party integrations) — for parameters that accept values which, when augmented with shell metacharacters, produce changed server behavior. A classic test payload appends a command separator and a benign command, for example injecting a value containing ; id or $(id) or `id` into a parameter. If the application response, output files, or a downstream side effect reveals command output or execution, the injection point is confirmed.

4. Payload Execution and Post-Exploitation. Once an injectable parameter is confirmed, the attacker substitutes an arbitrary command. Because the process runs on the server, the attacker can:

   • Read sensitive files (application configuration, database credentials, secrets) with the service account's privileges.
   • Establish persistence (cron jobs, injected code, added SSH keys) or a reverse shell for interactive access.
   • Move laterally to reachable internal hosts, since the Tuleap server often sits adjacent to CI/CD runners, databases, and source code repositories.
   • Exfiltrate source code and project data, or tamper with build artifacts and repositories — a supply-chain risk for organizations that use Tuleap to manage software delivery.

Because AC is Low and UI is None, exploitation is scriptable and reliably repeatable against a known-vulnerable instance by any authenticated low-privileged user.

Impact Assessment

The business impact is severe. Arbitrary OS command execution on an ALM server compromises the confidentiality, integrity, and availability of the platform and any data or systems it touches (CVSS subscores C:H/I:H/A:H). Tuleap commonly holds intellectual property (source code, requirements, test cases), project planning data, and integration credentials for downstream systems. A compromised ALM server is a high-value target: it can be used to inject malicious code into build pipelines (software supply-chain compromise), exfiltrate proprietary source, or pivot into internal networks where CI runners, artifact repositories, and databases reside.

The blast radius extends beyond the Tuleap host itself. If the appliance is integrated with version control (Git/SVN), CI systems, or external trackers, an attacker operating from the Tuleap server inherits those trust relationships. Persistence established at the OS layer can survive application updates and evades application-level monitoring.

Constraints that slightly narrow the immediate exposure but not the severity: the attack requires a valid low-privileged account (PR:L), so purely anonymous external actors must first obtain credentials or a registration. Internally, however, any employee, contractor, or self-registered user can mount the attack. The network attack vector (AV:N) means no local or adjacent access is required. Overall the risk is high, and the absence of a vendor patch (patch confidence 0/4) elevates urgency.

Detection Guidance

Given the absence of public exploit details, the detection rules below target the generic indicators of OS command injection against a Tuleap web tier: shell metacharacter sequences in HTTP request data and suspicious child-process spawning by the web server. These are behavioral detections that may require tuning to the deployed environment and to Tuleap's normal request patterns.

Sigma Rule

title: Potential OS Command Injection Against Tuleap (CWE-78)
id: 9f2c7a1e-3b6d-4e5a-9c1f-tuleap105407
status: experimental
description: Detects HTTP requests containing common OS command injection metacharacter patterns targeting a Tuleap web front end. High false-positive potential; correlate with response anomalies.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-105407
author: Threat Intelligence
date: 2026/01/01
logsource:
  category: webserver
  product: apache
  service: access
detection:
  selection_method:
    cs-method:
      - GET
      - POST
  selection_meta:
    cs-uri-query|contains:
      - ';'
      - '|'
      - '&&'
      - '`'
      - '$(('
  selection_cmd:
    cs-uri-query|contains:
      - 'id'
      - 'whoami'
      - 'curl '
      - 'wget '
      - 'nc '
      - '/bin/bash'
      - '/bin/sh'
      - 'chmod '
      - 'base64 -d'
  condition: selection_method and selection_meta and selection_cmd
falsepositives:
  - Legitimate application parameters containing shell-like characters
  - Security scanners and fuzzing tools
level: high

YARA Rule

rule CVE_2026_105407_Tuleap_Command_Injection
{
    meta:
        description = "Detects command-injection payload artifacts and Tuleap-related exploit markers referencing CVE-2026-105407 in captured HTTP traffic or web logs"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-105407"
        cve = "CVE-2026-105407"
        author = "Threat Intelligence"
        date = "2026-01-01"
        severity = "high"
    strings:
        $tuleap = "Tuleap" ascii nocase
        $cve    = "CVE-2026-105407" ascii
        $metachar1 = ";" wide ascii
        $metachar2 = "&&" wide ascii
        $metachar3 = "$(" wide ascii
        $shell1 = "/bin/sh" ascii
        $shell2 = "/bin/bash" ascii
        $cmd1   = "whoami" ascii
        $cmd2   = "curl -" ascii
        $cmd3   = "wget " ascii
    condition:
        ($cve) or
        ($tuleap and 1 of ($metachar*) and 1 of ($shell*, $cmd*))
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-105407 Tuleap OS Command Injection Attempt"; flow:established,to_server; http.method; content:"GET"|"POST"; http.uri; pcre:"/(%3B|;|%7C|\||%26%26|&&|%60|`|\$\(|%24%28)/Ui"; http.uri; pcre:"/(whoami|id%20|curl%20|wget%20|%2Fbin%2F(sh|bash)|\/bin\/(sh|bash)|base64%20-d)/Ui"; reference:cve,CVE-2026-105407; classtype:web-application-attack; sid:1054070; rev:1;)

Elastic Detection

sequence by source.ip with maxspan=1m
  [ network where event.category == "network" and
      url.query matches~ ".*(;|\\||&&|`|\\$\\().*" ]
  [ network where event.category == "network" and
      url.query matches~ ".*(whoami|/bin/sh|/bin/bash|curl |wget |base64 -d).*" ]

Splunk SPL Query

index=web sourcetype=access_combined OR sourcetype=apache:access
| eval uri_lower = lower(uri)
| where match(uri_lower, "(;|%3b|\||%7c|&&|%26%26|`|%60|\$\(|%24%28)")
    AND match(uri_lower, "(whoami|%2fbin%2f|/bin/sh|/bin/bash|curl\+|wget\+|base64\+-d|chmod\+)")
| stats count min(_time) as first_seen max(_time) as last_seen values(uri) as uris by src_ip, host
| where count >= 1
| sort - count

Tune the parenthesized keyword lists to the deployment; broad metacharacter matching alone will generate noise from normal encoded parameters, so the two-stage match requirement (metacharacter AND command keyword) is intentional.

Wazuh OSSEC Rule

<group name="web,attack,cve-2026-105407">
  <rule id="105407" level="12">
    <if_sid>31100,31101,31103,31104</if_sid>
    <id>^CVE-2026-105407</id>
    <description>CVE-2026-105407: Possible Tuleap OS command injection attempt detected in web request</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>cve_2026_105407,command_injection,</group>
  </rule>

  <rule id="105408" level="12">
    <decoded_as>web-accesslog</decoded_as>
    <regex type="pcre2">(?i)(?:%3[bB]|;|%7[cC]|\||%26%26|&&|%60|`|\$\(|%24%28).*(?:whoami|%2[fF]bin%2[fF]|/bin/(?:sh|bash)|base64\+-d|curl\+|wget\+)</regex>
    <description>CVE-2026-105407: Shell metacharacter and command keyword observed in URL - possible OS command injection against Tuleap</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>cve_2026_105407,command_injection,web,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 — UNPATCHED. No patch evidence from any tracked source. No vendor fix or workaround is documented in the available data. Because there is no confirmed vendor patch, mitigation must rely on defense-in-depth controls and reduced exposure until a fix is released.

1) Immediate mitigations

• Restrict network exposure. Do not leave Tuleap Enterprise Edition 17.0–17.5 directly reachable from the internet. Place the instance behind a VPN, zero-trust access proxy, or reverse proxy that enforces strong authentication. This directly counters the AV:N vector.
• Tighten authentication and privilege. Since PR:L is required, minimize the population of accounts that can reach the application. Disable open/self-registration if it is not essential. Enforce MFA and audit all existing low-privileged accounts; rotate credentials for users who may have been phished.
• Harden the service context. Run the Tuleap web/service account with least privilege, in a restricted container or with a constrained AppArmor/SELinux profile that blocks spawning of unexpected shells and interpreters (e.g., deny exec of /bin/sh, /bin/bash). Restrict outbound network egress from the Tuleap host to break reverse-shell and exfiltration paths.
• Monitor and alert. Deploy the detection guidance above; enable verbose logging of authenticated request parameters on the Tuleap front end and alert on shell metacharacter and command-keyword co-occurrence.
• Segment. Isolate the Tuleap host from CI runners, source-control servers, and databases at the network layer so that command execution on the host does not automatically yield downstream trust.

2) Patch / upgrade steps

• Monitor the Tuleap vendor release notes and security advisories continuously. As soon as a fixed version beyond 17.5 is published, schedule an upgrade of all affected instances (17.0–17.5).
• If a hotfix or patch is issued, validate it against a staging instance before production rollout, and confirm the vulnerable code path is actually closed by retesting the trigger conditions.
• Until then, treat the affected versions as vulnerable and continue compensating controls. Do not assume that applying an unrelated update resolves this CVE.

3) Long-term hardening

• Adopt a secure coding standard that mandates parameterized/whitelisted invocation of external commands (e.g., avoid shell string concatenation; use argument arrays and avoid shell=True/system()-style calls where the CWE-78 class originates), and enforce it through code review and SAST/DAST gates.
• Run the Tuleap web tier in a container with a read-only root filesystem, no shell, and a minimal base image to remove the interpreter binaries an injection would rely on.
• Enforce full-fidelity logging, centralized SIEM correlation, and periodic purple-team exercises that attempt authenticated command injection against ALM platforms.
• Maintain an asset inventory of ALM/DevOps tooling and subscribe to vendor advisories so future CVEs of this class are detected and remediated promptly.

References

• NVD — CVE-2026-105407: https://nvd.nist.gov/vuln/detail/CVE-2026-105407
• MITRE CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'): https://cwe.mitre.org/data/definitions/78.html
• MITRE ATT&CK T1190 — Exploit Public-Facing Application: https://attack.mitre.org/techniques/T1190/
• Tuleap security advisories and release notes: https://tuleap.org/ (monitor for vendor-issued fix covering 17.0–17.5)
• CISA Known Exploited Vulnerabilities catalog (checked; CVE-2026-105407 is not listed as of this report): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

No threat actor campaigns or in-the-wild exploitation evidence are associated with CVE-2026-105407 in the available data. No public PoC, Nuclei template, or exploit code is known.