CVE-2026-84285

Executive Summary

CVE-2026-84285 is an OS Command Injection vulnerability (CWE-78) affecting Tuleap Enterprise Edition versions 17.3 through 17.5. A remote attacker with low-privileged authenticated access can inject and execute arbitrary operating system commands on the server hosting the Tuleap application. Successful exploitation results in full compromise of the confidentiality, integrity, and availability of the affected host, and potentially lateral movement into connected infrastructure.

Technical Analysis

This vulnerability is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command, commonly referred to as OS Command Injection). The affected product is Tuleap Enterprise Edition, a web-based application lifecycle management (ALM) and DevOps platform. The vulnerability spans versions 17.3 through 17.5.

The core weakness class — OS command injection — arises when an application passes user-controllable input into a system shell or command execution function without adequate sanitization or parameterization. In a web application context, this typically occurs when the application constructs a shell command string from request-supplied data and then invokes it through a shell interpreter (for example, via a system call that interprets shell metacharacters such as ;, |, &&, backticks, or $()). When input is not neutralized, an attacker can append or embed their own commands, which the underlying operating system will execute with the privileges of the web application's process.

The CVSS vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H indicates:

• AV:N (Network) — the vulnerable component is reachable over the network, consistent with a web-facing ALM platform.
• AC:L (Low) — no specialized conditions or race windows are required.
• PR:L (Low) — the attacker must possess some level of authenticated access (a low-privileged account), meaning the attack is not anonymous.
• UI:N (None) — no victim interaction is required.
• S:U (Unchanged) — the impact is confined to the vulnerable component's security scope.
• C/I/A:H (High) — full compromise of confidentiality, integrity, and availability.

The precise request parameter, endpoint, or code path that fails to sanitize input is not disclosed in the available intelligence (the NVD description provides no endpoint, function, file path, or parameter names). Accordingly, this report analyzes the vulnerability strictly at the class and mechanism level and does not fabricate implementation specifics. No CVE CNA title details expand the technical scope beyond the NVD description quoted above.

The attack surface is the Tuleap Enterprise Edition web interface. Because the precondition is PR:L, the injection point is most plausibly in an authenticated feature that bridges web input to a server-side shell operation — such as an administrative, integration, or project-configuration function. However, because no specific feature is named in the source data, the exact injection point must be determined through vendor guidance or independent testing once available.

Exploitation Scenarios

The following attack chain is described at the vulnerability-class level, as required. No public proof-of-concept, Nuclei template, or exploit code exists for this CVE per the supplied data. No public PoC is available; the attack chain is inferred from the vulnerability class.

1. Reconnaissance / target identification. An attacker identifies internet- or intranet-exposed Tuleap Enterprise Edition instances, for example via HTTP fingerprinting (page titles, static asset paths, or the application favicon). Version 17.3 through 17.5 is the affected window, so banner or asset version disclosure can narrow candidate targets. The attacker then requires a valid low-privileged account, consistent with the PR:L metric.

2. Triggering the flaw class. Using authenticated access, the attacker locates a feature that causes the application to construct and execute a server-side shell command from user-controllable input. In an OS command injection, the attacker supplies input containing shell metacharacters or command chaining syntax so that the crafted value is interpreted by the shell rather than treated as inert data. Because the specific parameter is not disclosed in the source data, the exact delivery vector must be established from vendor advisory or testing; the mechanism is injection of shell metacharacters into an unsanitized input that reaches a command execution sink.

3. Payload / execution method. At the vulnerability-class level, the attacker crafts input that appends or embeds an operating system command, causing the web application process to execute it on the host. The payload executes with the privileges of the Tuleap web/service account. Execution may be used for command output exfiltration, file read/write, or establishing a reverse shell depending on environment constraints.

4. Post-exploitation impact. With arbitrary command execution, the attacker can read sensitive configuration and data, modify or destroy application and system files, and pivot to adjacent systems reachable from the compromised host. Given C/I/A:H, the outcome is full loss of confidentiality, integrity, and availability for the affected instance.

Impact Assessment

The CVSS base score is 8.8 (High) with vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

• Confidentiality (High): OS command execution exposes application source, configuration, secrets, database credentials, and potentially repository contents managed by the ALM platform.
• Integrity (High): The attacker can alter application files, inject data, or tamper with source repositories and build artifacts.
• Availability (High): Arbitrary commands can stop services, delete data, or render the host unusable.
• Blast radius: The immediately affected asset is the Tuleap Enterprise Edition host (17.3–17.5). Because Tuleap frequently integrates with CI/CD systems, source control, and identity providers, a compromised instance can become a pivot point into the surrounding DevOps toolchain.

EPSS: Not yet scored by FIRST.org. No EPSS value is asserted here. CISA KEV: Not listed. Exploitation in the wild: No public exploit, PoC, or Nuclei template was identified in the supplied data; no known threat-actor campaign is associated.

Detection Guidance

Detection focuses on identifying shell metacharacter injection attempts against the Tuleap web interface and anomalous child-process spawning by the web/service account. Because the exact endpoint is undisclosed, detections are written to trigger on generic command-injection indicators.

Sigma Rule

title: Potential OS Command Injection Attempt Against Tuleap Enterprise Edition (CVE-2026-84285)
id: 8a1f2c74-3b6e-4d2a-9f10-7c5e0d8b4a61
status: experimental
description: Detects shell metacharacter injection patterns in HTTP requests targeting Tuleap, indicative of CWE-78 exploitation attempts.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-84285
author: valtersit.com
date: 2026/01/01
logsource:
  category: webserver
detection:
  selection_method:
    cs-method:
      - GET
      - POST
  selection_meta:
    cs-uri-query|contains:
      - ';'
      - '|'
      - '&&'
      - '$('
      - '`'
      - '>%20'
  selection_cmd:
    cs-uri-query|contains:
      - 'cmd='
      - 'exec='
      - '/bin/sh'
      - '/bin/bash'
      - 'whoami'
      - 'id%20'
      - 'curl%20'
      - 'wget%20'
  condition: selection_method and (selection_meta and selection_cmd)
falsepositives:
  - Legitimate application traffic containing encoded shell-like characters
  - Security scanners and fuzzing tools
level: high

YARA Rule

rule CVE_2026_84285_Tuleap_OS_Command_Injection
{
    meta:
        description = "Detects OS command injection payload patterns targeting Tuleap Enterprise Edition (CVE-2026-84285)"
        author = "valtersit.com"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-84285"
        date = "2026-01-01"
        severity = "high"

    strings:
        $cwe = "CWE-78" ascii wide nocase
        $p1 = ";id" ascii nocase
        $p2 = ";whoami" ascii nocase
        $p3 = "|whoami" ascii nocase
        $p4 = "$(id)" ascii nocase
        $p5 = "`id`" ascii nocase
        $p6 = ";/bin/sh" ascii nocase
        $p7 = "&&/bin/bash" ascii nocase
        $p8 = ";curl " ascii nocase
        $p9 = ";wget " ascii nocase
        $p10 = "%3Bid" ascii nocase

    condition:
        (uint16(0) == 0x3C3F) or
        any of ($p*) or $cwe
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-84285 Tuleap Enterprise Edition OS Command Injection Attempt"; flow:established,to_server; http.method; content:"GET" or content:"POST"; http.uri; content:";"; nocase; http.uri; content:"whoami" or content:"id" or content:"/bin/sh" or content:"/bin/bash"; nocase; reference:cve,2026-84285; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-84285; classtype:web-application-attack; sid:202684285; rev:1;)

Elastic Detection

sequence by source.ip with maxspan=5s
  [ network where event.action == "network_flow" and network.transport == "tcp"
    and url.query : ("*;id*", "*;whoami*", "*|whoami*", "*$(id)*", "*`id`*", "*/bin/sh*", "*/bin/bash*", "*%3Bid*") ]

Splunk SPL Query

index=web sourcetype=access_combined OR sourcetype=tuleap_access
| eval uri_lower=lower(uri)
| where match(uri_lower, "(%3b|;|\||&&|\$\(|`).*(id|whoami|/bin/(sh|bash)|curl|wget|nc )")
| stats count min(_time) as first_seen max(_time) as last_seen by src_ip, uri, status
| where count > 0
| sort - count

Wazuh OSSEC Rule

<group name="web,tuleap,cve_2026_84285,">
  <rule id="100842" level="12">
    <if_sid>31100</if_sid>
    <id>^200$|^300$|^403$|^500$</id>
    <url>;|%3B|\||&&|\$\(|`</url>
    <description>CVE-2026-84285: Possible OS command injection attempt against Tuleap Enterprise Edition</description>
    <mitre>
      <id>T1190</id>
      <id>T1059</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source). No vendor fix, workaround, or affected-version package data was identified. The guidance below is risk-reduction oriented.

1. Immediate mitigations

   • Restrict network exposure of Tuleap Enterprise Edition 17.3–17.5 to trusted networks; place behind VPN or zero-trust access proxy.
   • Enforce least privilege: minimize the number of low-privileged accounts and audit their capabilities, given the PR:L attack precondition.
   • Apply web application firewall (WAF) rules to block shell metacharacter patterns in request parameters.
   • Monitor for unexpected child processes spawned by the Tuleap web/service account.

2. Patch / upgrade steps

   • No patch is currently available. Track the vendor (Tuleap) security advisory channel for a fixed release and apply it as soon as it is published.
   • Until a fix exists, treat the instance as vulnerable and compensate with network segmentation and monitoring.

3. Long-term hardening

   • Run the Tuleap application under a dedicated least-privilege OS account with no unnecessary shell access or sudo rights.
   • Harden the host with mandatory access controls (SELinux/AppArmor) to constrain command execution.
   • Deploy egress filtering to limit reverse-shell and data-exfiltration channels.
   • Maintain asset inventory and version tracking for ALM/DevOps platforms to enable rapid patch response.

References

1. NVD — CVE-2026-84285: https://nvd.nist.gov/vuln/detail/CVE-2026-84285
2. MITRE CWE-78 — OS Command Injection: https://cwe.mitre.org/data/definitions/78.html
3. MITRE ATT&CK T1190 — Exploit Public-Facing Application: https://attack.mitre.org/techniques/T1190/
4. MITRE ATT&CK T1059 — Command and Scripting Interpreter: https://attack.mitre.org/techniques/T1059/
5. Tuleap Security Advisories (vendor): https://tuleap.org/security/ (consult for patch status)

No threat actor campaigns or in-the-wild exploitation evidence were identified. CISA KEV status: NOT listed. EPSS: not yet scored.