VulnerabilityPublished 15 Sep 2026

CVE-2026-82191: j2commerce.com J2Store extension for Joomla · Use of Predictable Algorithm in Random Number Generator

Affects j2commerce.com J2Store extension for JoomlaSource CVE Database V5

Compare

Not known to be exploited · CVSS 5.3 Medium.

Data as of 30 Oct 2026, 20:25 UTC

CVSS 4.0 base score

5.3Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: Passive
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: Passive: Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system 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 to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 15 Sep 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 30 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.
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-hv62-7458-mg3v

What to do

Affected software

Product	Affected	Fixed in
j2commerce.comJ2Store extension for Joomla	Affected =1.0.0-3.3.22 =4.0.0-4.0.22 =4.1.0-4.1.7	Fixed in–

AI-suggested

Since exploitation requires user interaction and does not grant additional unauthorized access, mitigation may include educating users to avoid clicking suspicious links and monitoring for unusual redirect behavior. Follow vendor advisories for updates on patches or official fixes.

Description

Joomla Extension - j2commerce.com - Unescaped request data reflected into PayPal notify redirect in J2Store 1.0.0-3.3.2, 4.0.0-4.0.22, 4.1.0-4.1.7 - A crafted link to the paypal notify endpoint, if followed by a victim's browser (or an automated system that fetches it), causes the resulting redirect to `com_j2store`'s checkout controller to carry attacker-chosen query parameters instead of only the intended `view=checkout&task=confirmPayment&orderpayment_type=...&paction=process` set — parameter injection/smuggling into that follow-up request. This requires a victim to load the crafted link (`UI:R`/`UI:P`); it does not by itself grant an unauthenticated attacker anything they could not already obtain by requesting the target `com_j2store` URL directly with their own parameters.

Impact

The vulnerability allows an attacker to inject arbitrary query parameters into a redirect URL after a PayPal notify request if a victim loads a crafted link. However, it does not provide unauthorized access or additional capabilities beyond what an attacker could achieve by directly requesting the affected URL with chosen parameters. The impact is limited to potential manipulation of the redirect parameters, which may affect the user experience or workflow but does not compromise confidentiality, integrity, or availability of the system.

Summary

The J2Store extension for Joomla contains a vulnerability (CVE-2026-82191) where unescaped request data is reflected into the PayPal notify redirect endpoint. When a victim's browser or an automated system follows a crafted link to this endpoint, the resulting redirect to the checkout controller includes attacker-injected query parameters instead of the intended fixed parameters. This parameter injection or smuggling requires user interaction (loading the crafted link) and does not elevate privileges or expose new information beyond what is accessible by direct requests with manipulated parameters.

CWE-1241Use of Predictable Algorithm in Random Number Generator (opens in a new tab)
Base weaknessOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The device uses an algorithm that is predictable and generates a pseudo-random number.
Architecture and Design · Implementation
It is highly recommended to use a true random number generator (TRNG) to ensure the security of encryption schemes. Hardware-based TRNGs generate unpredictable, unbiased, and independent random numbers because they employ physical phenomena, e.g., electrical noise, as sources to generate random numbers.
OWASP Cheat Sheets
Forgot Password (opens in a new tab)
Transport Layer Protection (opens in a new tab)
User Privacy Protection (opens in a new tab)
Password Storage (opens in a new tab)
Cryptographic Storage (opens in a new tab)
OWASP ASVS 4.0.3
V2.3.1 (opens in a new tab)
V2.6.2 (opens in a new tab)
V2.7.6 (opens in a new tab)
Attack patterns
Cryptanalysis (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

j2commerce.com (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 15 Sep 2026, 19:16 UTC

WeaknessesCWE-1241

Technical details

References

Community reviews

Related threats