CVE-2025-55129VulnerabilityPublished 2 Dec 2025

CVE-2025-55129: Revive Adserver · Vulnerability

Affects Revive AdserverSource CVE Database V5

Mentioned vulnerabilities

CVE-2025-52672

Not known to be exploited · CVSS 5.4 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.0 base score

5.4Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on 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 2 Dec 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 2026-10-25.

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
Revive Revive Adserver	Affected =6	Fixed in–

AI-suggested

1. Monitor Revive’s official channels closely for patches addressing CVE-2025-55129 and apply them promptly once available. 2. Implement strict username validation routines that detect and block homoglyph characters or visually similar Unicode characters to prevent impersonation attempts. 3. Enforce multi-factor authentication (MFA) for user accounts to reduce the risk of unauthorized access even if username spoofing occurs. 4. Conduct regular audits of user accounts and access logs to identify suspicious activities or duplicate usernames that may indicate impersonation. 5. Educate administrators and users about homoglyph attacks and encourage vigilance when reviewing usernames or account changes. 6. Consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block suspicious username patterns. 7. Limit privileges of user accounts to the minimum necessary to reduce the impact of potential impersonation. 8. Use monitoring tools to detect anomalies in ad campaign configurations or unexpected changes that could indicate compromise.

Description

HackerOne community member Kassem S.(kassem_s94) has reported that username handling in Revive Adserver was still vulnerable to impersonation attacks after the fix for CVE-2025-52672, via several alternate techniques. Homoglyphs based impersonation has been independently reported by other HackerOne users, such as itz_hari_ and khoof.

Impact

For European organizations relying on Revive Adserver, this vulnerability poses a risk to the confidentiality and integrity of their advertising infrastructure. Successful impersonation could allow attackers to manipulate ad campaigns, redirect revenue streams, or access sensitive campaign data. This could lead to financial losses, reputational damage, and erosion of trust with advertisers and partners. Given the importance of digital advertising in Europe’s economy, especially in countries with large media and marketing sectors, the impact could be significant. Additionally, compromised ad servers could be used as a vector for further attacks, including spreading malicious ads or conducting fraud. The medium severity rating reflects that while the vulnerability does not directly impact system availability, the potential for unauthorized access and data manipulation is non-trivial. Organizations with weak username validation or insufficient monitoring are particularly at risk.

Summary

CVE-2025-55129 is a vulnerability identified in Revive Adserver version 6, a widely used open-source ad serving platform. The issue relates to username handling mechanisms that remain susceptible to impersonation attacks despite a prior fix for CVE-2025-52672. Attackers can exploit this vulnerability by leveraging alternate techniques, notably homoglyph substitution, where visually similar characters are used to create deceptive usernames that mimic legitimate ones. This can lead to unauthorized access or manipulation of user accounts within the ad server environment. The vulnerability is characterized by a CVSS 3.0 base score of 5.4, indicating medium severity. It requires network access with low privileges (PR:L), no user interaction (UI:N), and affects confidentiality and integrity (C:L/I:L) but not availability (A:N). The weakness is classified under CWE-176, which pertains to improper handling of Unicode characters, facilitating spoofing attacks. No public exploits have been reported yet, but the presence of multiple independent reports highlights the persistence and potential impact of this flaw. The lack of an official patch at the time of reporting necessitates proactive mitigation strategies. This vulnerability could allow attackers to impersonate legitimate users, potentially leading to unauthorized changes in ad campaigns, data leakage, or disruption of advertising operations.

CWE-176Improper Handling of Unicode Encoding (opens in a new tab)
Variant weakness
The product does not properly handle when an input contains Unicode encoding.
Architecture and Design · Input Validation
Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Unvalidated Redirects and Forwards (opens in a new tab)
XML Security (opens in a new tab)
XML External Entity Prevention (opens in a new tab)
File Upload (opens in a new tab)
Input Validation (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.2 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
Using Unicode Encoding to Bypass Validation Logic (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

hackerone.com/reports/3434156 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 9 Dec 2025, 04:31 UTC

WeaknessesCWE-176

Technical details

References

Community reviews

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