Is CVE-2026-43827 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-43827 being exploited in the wild.

How severe is CVE-2026-43827?

Medium severity, with a CVSS score of 4, published 25 May 2026.

Which products and versions are affected?

Apache Shiro 1.0 to 2.1.0, 3.0.0-alpha-1; org.apache.shiro:shiro-core (Maven) ECOSYSTEM:introduced=1.0.0-incubating,fixed=2.2.0.

Is there a fix for CVE-2026-43827?

Yes. org.apache.shiro:shiro-core (Maven): upgrade to 2.2.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-43827 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-43827?

Check whether you run Apache Shiro or org.apache.shiro:shiro-core (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-43827: Apache Shiro session fixation in default configuration

CVE-2026-43827 · Severity: medium · CVSS 4 · Published 2026-05-25

Apache Shiro, a widely used security framework for Java applications, contains a flaw in its default configuration that fails to refresh user session identifiers after a successful login. This could allow an attacker to hijack a legitimate user's session if they can first trick the user into using a pre-defined session ID. If exploited, an attacker could gain unauthorized access to the user's account and sensitive data within the application.

Technologies: Apache Shiro, org.apache.shiro:shiro-core (Maven). Vendors: Apache, Maven.

Quick answers

Is CVE-2026-43827 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-43827 being exploited in the wild.
How severe is CVE-2026-43827?: Medium severity, with a CVSS score of 4, published 25 May 2026.
Which products and versions are affected?: Apache Shiro 1.0 to 2.1.0, 3.0.0-alpha-1; org.apache.shiro:shiro-core (Maven) ECOSYSTEM:introduced=1.0.0-incubating,fixed=2.2.0.
Is there a fix for CVE-2026-43827?: Yes. org.apache.shiro:shiro-core (Maven): upgrade to 2.2.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-43827 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-43827?: Check whether you run Apache Shiro or org.apache.shiro:shiro-core (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

org.apache.shiro:shiro-core (Maven): upgrade to 2.2.0 or later

# set org.apache.shiro:shiro-core to 2.2.0 in your pom.xml or build.gradle

Technical details

A session fixation vulnerability (CWE-384) exists in Apache Shiro's default configuration. The root cause is that the framework does not invalidate an existing session or rotate the session ID when a user successfully authenticates. An attacker can exploit this by providing a known session identifier to a victim's browser; once the victim logs in using that identifier, the attacker can use the same ID to access the authenticated session. This affects versions 1.0 through 2.1.0 and 3.0.0-alpha-1. The issue is resolved in versions 2.2.0 and 3.0.0-alpha-2 by ensuring a new session ID is generated upon login.

Affected products

Apache Shiro 1.0 to 2.1.0, 3.0.0-alpha-1

Identifiers

CVE-2026-43827
GHSA-fcvm-3cpj-f9qx

Timeline

2026-05-25: disclosed: Initial disclosure by Apache Software Foundation
2026-05-26: advisory: GitHub Advisory published

References

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