VulnerabilityPublished 19 Aug 2025Updated 29 Aug 2025

CVE-2025-54336: Plesk Obsidian · Incorrect Comparison

Source CVE Database V5

Not known to be exploited · CVSS 9.8 Critical.

Data as of 26 Oct 2026, 16:39 UTC

CVSS 3.1 base score

9.8Critical

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 45% 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:H/I:H/A:H

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

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: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 19 Aug 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 this vulnerability, European organizations should immediately upgrade Plesk Obsidian to a patched version once released by the vendor. In the interim, administrators should implement strict password policies avoiding passwords that start with "0e" followed by digits to prevent triggering the flawed comparison. Additionally, reviewing and modifying the authentication code to use strict comparison operators (===) instead of loose equality (==) is essential to prevent type juggling vulnerabilities. Organizations should also enable multi-factor authentication (MFA) for Plesk admin accounts to add an additional security layer. Monitoring login attempts and setting up alerts for suspicious activities can help detect exploitation attempts early. Network-level protections such as restricting access to the Plesk admin interface via IP whitelisting or VPNs can reduce exposure. Regular security audits and penetration testing focusing on authentication mechanisms will help identify similar weaknesses. Finally, educating administrators about this vulnerability and secure coding practices can prevent recurrence.

Description

In Plesk Obsidian 18.0.70, _isAdminPasswordValid uses an == comparison. Thus, if the correct password is "0e" followed by any digit string, then an attacker can login with any other string that evaluates to 0.0 (such as the 0e0 string). This occurs in admin/plib/LoginManager.php.

Impact

For European organizations, this vulnerability poses a severe risk, especially for those relying on Plesk Obsidian 18.0.70 for web hosting and server management. Successful exploitation grants attackers administrative access without valid credentials, enabling them to manipulate hosted websites, deploy malicious content, steal sensitive data, or disrupt services. This can lead to data breaches involving personal data protected under GDPR, resulting in regulatory penalties and reputational damage. Additionally, compromised servers can be leveraged for further attacks such as lateral movement within corporate networks, launching phishing campaigns, or distributing malware. The critical nature of the vulnerability means that attackers can operate stealthily without user interaction, increasing the likelihood of undetected breaches. European organizations in sectors like finance, healthcare, e-commerce, and government, which often use Plesk for hosting, are particularly at risk due to the sensitive nature of their data and services.

CWE-697Incorrect Comparison (opens in a new tab)
Pillar weakness
The product compares two entities in a security-relevant context, but the comparison is incorrect.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Double Encoding (opens in a new tab)
Client-side Injection-induced Buffer Overflow (opens in a new tab)
Command Delimiters (opens in a new tab)
Flash Injection (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

Description

AI analysisMachine-generated, updated 3 Sep 2025, 00:49 UTC

WeaknessesCWE-697

Technical details

References

Community reviews

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