critical · 9.1 Patched

Session Fixation in ipsilon

CVE-2016-8638 · GHSA-376m-3rm2-9jm6 · PYSEC-2026-360 · published 14 May 2022

How serious is it

  • Severity: critical, CVSS score 9.1 out of 10.
  • No exploit prediction (EPSS) score yet.
  • Not on the CISA list of exploited vulnerabilities.
  • No public exploit in Exploit-DB.

Is your app affected by CVE-2016-8638?

Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.

Who is affected

  • ipsilon (PyPI) >= 2.0.0, < 2.0.2
  • ipsilon (PyPI) >= 1.2.0, < 1.2.1
  • ipsilon (PyPI) >= 1.1.0, < 1.1.2
  • ipsilon (PyPI) >= 1.0.0, < 1.0.3

How to check

  1. Run pip show ipsilon in your project to see the installed version, including copies pulled in by other packages.
  2. Or paste your lockfile into the checker: it lists every package with a known vulnerability, this one included.
  3. Or run npx shippable-dev scan localhost:3000 in your project folder. It reads your lockfile and flags this vulnerability along with every other known one.

How to fix

Copies a prompt for Claude Code, Cursor or Codex: it checks your lockfiles for this and upgrades it.
  1. On >= 2.0.0, < 2.0.2: Upgrade ipsilon to 2.0.2 or later, commit the lockfile and redeploy.
  2. On >= 1.2.0, < 1.2.1: Upgrade ipsilon to 1.2.1 or later, commit the lockfile and redeploy.
  3. On >= 1.1.0, < 1.1.2: Upgrade ipsilon to 1.1.2 or later, commit the lockfile and redeploy.
  4. On >= 1.0.0, < 1.0.3: Upgrade ipsilon to 1.0.3 or later, commit the lockfile and redeploy.
  5. If a vulnerable version was live, check your logs and rotate the secrets that server could read.

The advisory

A vulnerability in ipsilon 2.0 before 2.0.2, 1.2 before 1.2.1, 1.1 before 1.1.2, and 1.0 before 1.0.3 was found that allows attacker to log out active sessions of other users. This issue is related to how it tracks sessions, and allows an unauthenticated attacker to view and terminate active sessions from other users. It is also called a "SAML2 multi-session vulnerability."

Check your whole app

Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.

References

Merged from GitHub Advisory Database, OSV. Last updated 28 Oct 2026. All vulnerabilities · RSS · JSON

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