VulnerabilityPublished 31 Jul 2025

CVE-2025-54834: OPEXUS FOIAXpress Public Access Link (PAL) · Observable Response Discrepancy

Affects OPEXUS FOIAXpress Public Access Link (PAL)Source CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 09:08 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
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: 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 impacted component.
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 31 Jul 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 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

Affected software

Product	Affected	Fixed in
OPEXUS FOIAXpress Public Access Link (PAL)	Affected =11.1.0	Fixed in–

AI-suggested

To mitigate this vulnerability, organizations should implement several specific measures: 1) Apply patches or updates from OPEXUS as soon as they become available to address the username enumeration flaw. 2) Implement server-side rate limiting on the /App/CreateRequest.aspx endpoint to restrict the number of requests from a single IP address or user agent within a given timeframe, thereby reducing the feasibility of automated enumeration attacks. 3) Modify the application logic to standardize responses regardless of username validity, ensuring that the endpoint returns identical status codes and messages whether or not a username exists, thus eliminating observable response discrepancies. 4) Employ web application firewalls (WAFs) with rules designed to detect and block suspicious enumeration patterns targeting this endpoint. 5) Monitor logs for unusual access patterns or spikes in requests to the vulnerable endpoint to enable early detection of exploitation attempts. 6) Educate users and administrators about the risks of username enumeration and encourage strong, unique passwords combined with multi-factor authentication (MFA) where possible to reduce the impact of compromised credentials. 7) Conduct regular security assessments and penetration testing focused on authentication and information disclosure vectors to proactively identify and remediate similar issues.

Description

OPEXUS FOIAXpress Public Access Link (PAL) version v11.1.0 allows an unauthenticated, remote attacker to query the /App/CreateRequest.aspx endpoint to check for the existence of valid usernames. There are no rate-limiting mechanisms in place.

Impact

For European organizations, especially governmental bodies, public institutions, or any entities using OPEXUS FOIAXpress PAL for managing public information requests, this vulnerability poses a significant privacy and security risk. The ability to enumerate valid usernames can lead to targeted phishing campaigns, social engineering, or brute-force password attacks against confirmed accounts. Given that FOIAXpress is often used by public sector organizations to handle sensitive information requests, the exposure of valid user accounts could undermine trust and lead to unauthorized access attempts. While the vulnerability does not directly compromise data integrity or availability, the information disclosure can serve as a stepping stone for more severe attacks. European organizations are also subject to strict data protection regulations such as GDPR, and failure to protect user information—even usernames—could result in regulatory scrutiny and penalties. Additionally, the lack of rate limiting exacerbates the risk by enabling attackers to perform large-scale automated attacks without detection or throttling.

CWE-204Observable Response Discrepancy (opens in a new tab)
Base weakness
The product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere.
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.
Implementation
Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended).
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (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
ICMP IP Total Length Field Probe (opens in a new tab)
ICMP IP 'ID' Field Error Message Probe (opens in a new tab)
Application Fingerprinting (opens in a new tab)
System Footprinting (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 31 Jul 2025, 18:02 UTC

WeaknessesCWE-204

Technical details

References

Community reviews

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