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/user/sessions endpoint allows detecting valid accounts

Moderate severity GitHub Reviewed Published Mar 9, 2021 in ezsystems/ezpublish-kernel • Updated Feb 3, 2026

Package

composer ezsystems/ezpublish-kernel (Composer)

Affected versions

>= 6.13.0, <= 6.13.8.0
>= 7.5.0, <= 7.5.15.0

Patched versions

6.13.8.1
7.5.15.1

Description

This Security Advisory is about a vulnerability in eZ Platform v1.13, v2.5, and v3.2, and in Ibexa DXP and Ibexa Open Source v3.3. The /user/sessions endpoint can let an attacker detect if a given username or email refers to a valid account. This can be detected through differences in the response data or response time of certain requests. The fix ensures neither attack is possible. The fix is distributed via Composer.

If you come across a security issue in our products, here is how you can report it to us: https://doc.ibexa.co/en/latest/guide/reporting_issues/#toc

References

@glye glye published to ezsystems/ezpublish-kernel Mar 9, 2021
Reviewed Mar 11, 2021
Published to the GitHub Advisory Database Mar 11, 2021
Last updated Feb 3, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(48th percentile)

Weaknesses

Observable Discrepancy

The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which exposes security-relevant information about the state of the product, such as whether a particular operation was successful or not. Learn more on MITRE.

CVE ID

CVE-2021-46876

GHSA ID

GHSA-gmrf-99gw-vvwj

Source code

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