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Fencer Vulns
critical 9.1

CVE-2016-8638 json

Session Fixation in ipsilon

published 2017-07-12 9 y ago modified 2026-10-27 12 d ago also GHSA-376m-3rm2-9jm6 , PYSEC-2026-360 , EUVD-2022-2125

cvss
9.1
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.1%
EPSS 2.1% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

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."

Patch / fix

  • pypi ipsilon 1.0.3, 1.1.2, 1.2.1, 2.0.2
  • ipsilon RHEL 7 1.0.0-13.el7_3
  • ipsilon-base RHEL 7 1.0.0-13.el7_3
  • ipsilon-saml2 RHEL 7 1.0.0-13.el7_3
  • ipsilon-client RHEL 7 1.0.0-13.el7_3
  • ipsilon-persona RHEL 7 1.0.0-13.el7_3
  • ipsilon-authform RHEL 7 1.0.0-13.el7_3
  • ipsilon-authldap RHEL 7 1.0.0-13.el7_3
  • ipsilon-infosssd RHEL 7 1.0.0-13.el7_3

red hat advisories RHSA-2016:2809

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-8638 updated cvss 8.2

ipsilon: DoS via logging out all open SAML2 sessions

  • Red Hat Enterprise Linux Server (v. 7) ipsilon 1.0.0-13.el7_3, ipsilon-base 1.0.0-13.el7_3, ipsilon-saml2 1.0.0-13.el7_3, ipsilon-client 1.0.0-13.el7_3, ipsilon-persona 1.0.0-13.el7_3, ipsilon-authform 1.0.0-13.el7_3, +6 more
    fixed: vendor fix RHSA-2016:2809

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.14% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 9.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:N/A:P
GitHub 3.0 9.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
OSV 3.0 9.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi ipsilon
>=2.0.0, <2.0.2
>=1.2.0, <1.2.1
>=1.1.0, <1.1.2
>=1.0.0, <1.0.3
2.0.2
1.2.1
1.1.2
1.0.3

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.