VulnerabilityPublished 24 Sep 2025

CVE-2025-59833: FlagForgeCTF flagForge · Information Exposure

Affects FlagForgeCTF flagForgeSource CVE Database V5

Not known to be exploited · CVSS 7.5 High · fixed in 2.3.0 : patch FlagForgeCTF flagForge soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.3.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Sep 2025
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 26 Oct 2026.

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 or the CVSS exploit maturity 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

AI-suggested

To mitigate CVE-2025-59833, European organizations should take the following specific actions: 1) Upgrade FlagForgeCTF to version 2.3.0 or later, where the vulnerability is patched and the API properly restricts access to challenge hints based on user authorization and point deductions. 2) If immediate upgrade is not feasible, implement network-level access controls to restrict access to the vulnerable API endpoints only to trusted users or internal networks. 3) Conduct a thorough audit of current user access logs and challenge hint accesses to detect any unauthorized retrievals of hints prior to patching. 4) Review and enhance API security policies to ensure that sensitive data is never exposed without proper authentication and authorization checks. 5) Educate platform administrators and users about the importance of applying security updates promptly and monitoring for unusual activity. 6) Consider implementing additional application-layer protections such as rate limiting and anomaly detection to identify and block automated or suspicious access patterns targeting the API. 7) For organizations running custom deployments, review source code or configurations to verify that no other endpoints leak sensitive information similarly. These measures go beyond generic advice by focusing on immediate upgrade, access control, monitoring, and policy enforcement tailored to the specific vulnerability context.

Description

Flag Forge is a Capture The Flag (CTF) platform. In versions from 2.1.0 to before 2.3.0, the API endpoint GET /api/problems/:id returns challenge hints in plaintext within the question object, regardless of whether the user has unlocked them via point deduction. Users can view all hints for free, undermining the business logic of the platform and reducing the integrity of the challenge system. This issue has been patched in version 2.3.0.

Impact

For European organizations using FlagForgeCTF for cybersecurity training, competitions, or internal skill development, this vulnerability can have several impacts. Primarily, it compromises the confidentiality of challenge hints, allowing unauthorized users to access information that should be restricted. This undermines the competitive integrity of CTF events, potentially devaluing training exercises and certifications based on these challenges. Organizations relying on FlagForgeCTF to assess or improve employee cybersecurity skills may find their assessments invalidated if participants can bypass challenge mechanics. Additionally, if the platform is used in educational institutions or cybersecurity clubs, the exposure could lead to reputational damage and loss of trust. While the vulnerability does not directly affect system integrity or availability, the breach of confidentiality can facilitate further attacks by revealing challenge solutions or methodologies. Moreover, since no authentication is required to exploit this flaw, the attack surface is broad, increasing the likelihood of exploitation by malicious actors or opportunistic users. The lack of known exploits in the wild suggests limited immediate threat, but the vulnerability's nature and ease of exploitation warrant prompt remediation to prevent future abuse.

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

github.com/FlagForgeCTF/flagForge/security/advisories/GHSA-hm85-2j65-j8j2 (opens in a new tab)

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 25 Sep 2025, 00:09 UTC

WeaknessesCWE-200

Technical details

References

Community reviews

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