CVE-2026-22604VulnerabilityPublished 10 Jan 2026Updated 12 Jan 2026

CVE-2026-22604: opf openproject · Information Exposure

Affects opf openprojectSource CVE Database V5

Not known to be exploited · CVSS 6.9 Medium : upgrade to 16.6.2 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score

6.9Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 22% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 16.6.2

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade openproject and opf/openproject to 16.6.2.

Affected software

Product	Affected	Fixed in
opfopenproject	Affected >=11.2.1 <16.6.2	Fixed in 16.6.2
GitHubopf/openproject`pkg:github/opf/openproject`Other threats	Affected >=11.2.1 <16.6.2	Fixed in 16.6.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

1. Upgrade OpenProject to version 16.6.2 or later, where the vulnerability is patched and username disclosure is eliminated. 2. If immediate upgrade is not feasible, implement web application firewall (WAF) rules to detect and block POST requests to /account/change_password containing the password_change_user_id parameter from untrusted sources. 3. Restrict access to the /account/change_password endpoint to authenticated users only, if possible, via access control configurations or reverse proxy rules. 4. Monitor server logs for unusual enumeration patterns, such as repeated POST requests with varying user IDs to the affected endpoint. 5. Educate users about phishing risks and encourage strong, unique passwords combined with multi-factor authentication to reduce the impact of potential credential-based attacks. 6. Conduct regular security assessments and vulnerability scans to identify outdated OpenProject instances and ensure timely patching. 7. Review and limit publicly exposed user information in error messages and API responses to minimize information leakage.

Description

OpenProject is an open-source, web-based project management software. For OpenProject versions from 11.2.1 to before 16.6.2, when sending a POST request to the /account/change_password endpoint with an arbitrary User ID as the password_change_user_id parameter, the resulting error page would show the username for the requested user. Since this endpoint is intended to be called without being authenticated, this allows to enumerate the user names of all accounts registered in an OpenProject instance. This issue has been patched in version 16.6.2.

Impact

For European organizations using vulnerable OpenProject versions, this vulnerability poses a risk primarily to user confidentiality. Exposure of usernames can enable attackers to conduct targeted phishing, social engineering, or brute force attacks against known accounts, potentially leading to unauthorized access if credentials are weak or reused. While the vulnerability does not directly compromise system integrity or availability, the information leakage can be a stepping stone for further attacks that may have more severe consequences. Organizations in sectors relying heavily on project management tools—such as IT, engineering, and government—may face increased risk due to the sensitive nature of project data and collaboration. Additionally, compliance with data protection regulations like GDPR may be impacted if user information is exposed without proper authorization. The vulnerability's ease of exploitation (no authentication or user interaction required) increases the likelihood of automated scanning and enumeration attempts, especially in environments exposed to the internet.

CWE-200Exposure of Sensitive Information to an Unauthorized Actor (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #20OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Subverting Environment Variable Values (opens in a new tab)
ICMP Echo Request Ping (opens in a new tab)
TCP SYN Scan (opens in a new tab)
Enumerate Mail Exchange (MX) Records (opens in a new tab)
DNS Zone Transfers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 17 Jan 2026, 07:49 UTC

WeaknessesCWE-200

Technical details

References

Community reviews

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