VulnerabilityPublished 13 Aug 2026

CVE-2026-59504: CWE-602 · Client-Side Enforcement of Server-Side Security

Source GCVE Database

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Authoritative record:CVE-2026-59504· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical.

Data as of 12 Nov 2026, 23:24 UTC

CVSS 3.1 base score

9.1Critical

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 37% 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:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
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: 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: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 13 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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.

ghsa-2wv9-fhg5-594v

What to do

Affected software

Product	Affected	Fixed in
PriorityPortal Generator addon to Priority ERP (developed by Soft Solutions)	Affected =All versions without Priwall v3	Fixed in–

AI-suggested

Until an official fix is available, users should review their applications to ensure that all critical security controls are enforced server-side rather than relying on client-side enforcement.

Description

CVE-2026-59504 is a critical vulnerability classified under CWE-602, involving client-side enforcement of security controls that should be enforced server-side. This flaw allows an attacker to bypass intended server-side security mechanisms by manipulating client-side controls. The vulnerability has a CVSS 3.1 score of 9.1, indicating high impact on confidentiality and integrity without requiring privileges or user interaction. No affected software versions or vendor patches are currently specified. There are no known exploits in the wild at this time.

Impact

The vulnerability can lead to unauthorized access or modification of sensitive data due to bypassing server-side security controls. Confidentiality and integrity are rated as high impact, while availability is not affected. This could result in significant security breaches if exploited.

Summary

This vulnerability, identified as CVE-2026-59504 and categorized under CWE-602, arises when security controls intended to be enforced on the server are instead enforced on the client side. This misplacement allows attackers to circumvent server-side security by manipulating client-side enforcement mechanisms. The CVSS 3.1 base score of 9.1 reflects a network attack vector with low attack complexity, no privileges required, no user interaction, and high confidentiality and integrity impacts.

CWE-602Client-Side Enforcement of Server-Side Security (opens in a new tab)
Class weaknessLikelihood of exploit: MediumOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product includes a server that relies on the client to implement a protection mechanism that is intended to protect the server.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely.
Architecture and Design
If some degree of trust is required between the two entities, then use integrity checking and strong authentication to ensure that the inputs are coming from a trusted source.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
Access Control (opens in a new tab)
Authorization Testing Automation (opens in a new tab)
OWASP ASVS 4.0.3
V1.4.1 (opens in a new tab)
V1.5.3 (opens in a new tab)
V4.1.1 (opens in a new tab)
Attack patterns
Manipulating Hidden Fields (opens in a new tab)
Create Malicious Client (opens in a new tab)
Removing Important Client Functionality (opens in a new tab)
Removing/short-circuiting 'Purse' logic: removing/mutating 'cash' decrements (opens in a new tab)
Accessing/Intercepting/Modifying HTTP Cookies (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 13 Aug 2026, 18:17 UTC

WeaknessesCWE-602

Technical details

References

Community reviews

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