Summary
/user/sessions endpoint allows detecting valid accounts
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
Impact
CVE-2021-46876 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (6.13.8.1, 7.5.15.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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ezsystems/ezpublish-kernel to 6.13.8.1 or later; ezsystems/ezpublish-kernel to 7.5.15.1 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2021-46876? CVE-2021-46876 is a medium-severity security vulnerability in ezsystems/ezpublish-kernel (composer), affecting versions >= 6.13.0, <= 6.13.8.0. It is fixed in 6.13.8.1, 7.5.15.1.
- How severe is CVE-2021-46876? CVE-2021-46876 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of ezsystems/ezpublish-kernel are affected by CVE-2021-46876? ezsystems/ezpublish-kernel (composer) versions >= 6.13.0, <= 6.13.8.0 is affected.
- Is there a fix for CVE-2021-46876? Yes. CVE-2021-46876 is fixed in 6.13.8.1, 7.5.15.1. Upgrade to this version or later.
- Is CVE-2021-46876 exploitable, and should I be worried? Whether CVE-2021-46876 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2021-46876 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2021-46876?
- Upgrade
ezsystems/ezpublish-kernelto 6.13.8.1 or later - Upgrade
ezsystems/ezpublish-kernelto 7.5.15.1 or later
- Upgrade