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CVE-2026-43827

MEDIUM

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…

Published
May 25, 2026
Updated
Jun 17, 2026
Affected
0 pkgs
Patched
None yet
Exploits
None indexed

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 Products

1 product · 2 configurations
Application
shiroapache
< 2.1.1
1 version
3.0.0

Detection & mitigation playbook

Vendor / appliance
  1. Detect

    Inventory every apache shiro deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.

  2. Fix

    Apply the apache shiro security patch or hotfix for CVE-2026-43827 on the affected version, following the vendor advisory for your exact build.

  3. Workarounds

    Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.

  4. How O3 protects you

    O3 detects and blocks CVE-2026-43827 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Tailored to CVE-2026-43827. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

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 · Runtime Protection

Is CVE-2026-43827 being exploited in your environment?

O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2026-43827 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.