How severe is CVE-2026-43827?

No CVSS score has been assigned to CVE-2026-43827 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-43827?

CVE-2026-43827 affects the following packages: org.apache.shiro:shiro-core (Maven), org.apache.shiro:shiro-core (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-43827?

Update org.apache.shiro:shiro-core to 2.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-43827 is resolved across your whole dependency graph.

How do I detect CVE-2026-43827 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.shiro:shiro-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-43827 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-43827 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-43827 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-43827?

CVE-2026-43827 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 43th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-43827?

CVE-2026-43827 is classified as CWE-384 (CWE-384). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-43827 published, and has it been updated?

CVE-2026-43827 was published on May 26, 2026 and was last updated on June 30, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

Not in CISA KEV

CVE-2026-43827 — shiro-core

CVE-2026-43827 is a CWE-384 vulnerability in org.apache.shiro:shiro-core. A fix is available for org.apache.shiro:shiro-core — see the affected versions and patch details below.

Apache Shiro has a session fixation vulnerability

Published

May 26, 2026

Updated

Jun 30, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-43827.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs43th percentile — riskier than 43% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

☕org.apache.shiro:shiro-core☕org.apache.shiro:shiro-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Default configurations of Apache Shiro have a session fixation vulnerability.

This issue affects Apache Shiro from 1.0 to 2.1.0, and 3.0.0-alpha-1.

Users are recommended to upgrade to version 2.1.1, or 3.0.0-alpha-2 or later, which fixes the issue.

In the affected versions, when a session already exists, it is not invalidated upon successful login, nor is a new session being generated with a new ID.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.shiro:shiro-core`	≥ 1.0.0-incubating&&< 2.2.0	2.2.0`org.apache.shiro:shiro-core:2.2.0`
☕Maven	`org.apache.shiro:shiro-core`	≥ 3.0.0-alpha-1&&< 3.0.0-alpha-2	3.0.0-alpha-2`org.apache.shiro:shiro-core:3.0.0-alpha-2`

Affected Products

1 product · 2 configurations

Application

shiroapache

< 2.1.1

1 version

3.0.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.shiro:shiro-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.shiro:shiro-core to 2.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-43827 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

Default configurations of Apache Shiro have a session fixation vulnerability. This issue affects Apache Shiro from 1.0 to 2.1.0, and 3.0.0-alpha-1. Users are recommended to upgrade to version 2.1.1, or 3.0.0-alpha-2 or later, which fixes the issue. In the affected versions, when a session already exists, it is not invalidated upon successful login, nor is a new session being generated with a new ID.

O3 Security · Impact-Aware SCA

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