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Fencer Vulns
high 7.5

CVE-2021-21671 json

Session fixation vulnerability in Jenkins

published 2021-06-30 5 y ago modified 2026-09-08 2 mo ago also BIT-jenkins-2021-21671 , EUVD-2022-2462 , GHSA-4wr9-2xc6-jmg5

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

Jenkins 2.299 and earlier, LTS 2.289.1 and earlier does not invalidate the previous session on login.

Patch / fix

  • maven org.jenkins-ci.main:jenkins-core 2.289.2, 2.300
  • bitnami jenkins 2.300.0
  • jenkins jenkins 2.289.2, 2.300
  • butane openshift 4.8 0.12.1-2.rhaos4.8.el8
  • jenkins openshift 4.8 2.289.3.1633554819-1.el8
  • jenkins openshift 4.6 2.289.2.1629437819-1.el8
  • jenkins openshift 4.7 2.289.2.1628252553-1.el8

red hat advisories RHSA-2021:3820RHBA-2021:3396RHBA-2021:3033

  • jenkins Arch Linux 2.300-1

arch linux advisories AVG-2118

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-2021-21671 updated cvss 7.5

jenkins: session fixation vulnerability

  • Red Hat OpenShift Container Platform 3.11 jenkins
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift Container Platform 4.6 jenkins 2.289.2.1629437819-1.el8
    fixed: vendor fix RHBA-2021:3396
  • Red Hat OpenShift Container Platform 4.7 jenkins 2.289.2.1628252553-1.el8
    fixed: vendor fix RHBA-2021:3033
  • Red Hat OpenShift Container Platform 4.8 jenkins 2.289.3.1633554819-1.el8
    fixed: vendor fix RHSA-2021:3820
  • Red Hat Fuse 7 jenkins Red Hat OpenShift Container Platform 4.6 jenkins-2-plugins 4.6.1629443573-1.el8, cri-o 1.19.3-11.rhaos4.6.git66a69b8.el7, cri-o 1.19.3-11.rhaos4.6.git66a69b8.el8, openshift 4.6.0-202108202025.p0.git.4c3480d.assembly.stream.el7, openshift 4.6.0-202108202025.p0.git.4c3480d.assembly.stream.el8, openshift-kuryr 4.6.0-202108202025.p0.git.0063daa.assembly.stream.el8, +13 more Red Hat OpenShift Container Platform 4.7 cri-o 1.20.4-8.rhaos4.7.git74c6592.el7, cri-o 1.20.4-8.rhaos4.7.git74c6592.el8 Red Hat OpenShift Container Platform 4.8 ovn2.13 20.12.0-140.el8fdp, butane 0.12.1-2.rhaos4.8.el8, ovn2.13-host 20.12.0-140.el8fdp, ovn2.13-vtep 20.12.0-140.el8fdp, ovn2.13-central 20.12.0-140.el8fdp, cri-o 1.21.3-6.rhaos4.8.gite34bf50.el7, +4 more
    not affected: vulnerable code not present

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

1.75% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 5.1 AV:N/AC:H/Au:N/C:P/I:P/A:P
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
maven org.jenkins-ci.main:jenkins-core
>=2.292, <2.300
<2.289.2
2.300
2.289.2
bitnami jenkins
>=2.266.0, <2.300.0
2.300.0

Affected products

  • Jenkins project Jenkins

Classification

Weakness
Technology feeds

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.