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CVE-2021-21615

Time-of-check Time-of-use (TOCTOU) Race Condition in Jenkins

5.3 MediumFix available

Jenkins 2.275 and LTS 2.263.2 allows reading arbitrary files using the file browser for workspaces and archived artifacts due to a time-of-check to time-of-use (TOCTOU) race condition.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
None
Availability
None

Exploit likelihood

0.91%Up 0.2 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 5.3

Jenkins 2.275 and LTS 2.263.2 allows reading arbitrary files using the file browser for workspaces and archived artifacts due to a time-of-check to time-of-use (TOCTOU) race condition.

Record
CVE-2021-21615
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS 2.0
3.5 LowAV:N/AC:M/Au:S/C:P/I:N/A:N
Weakness
CWE-367
Updated
2026-11-02
CVE List No score

Jenkins 2.275 and LTS 2.263.2 allows reading arbitrary files using the file browser for workspaces and archived artifacts due to a time-of-check to time-of-use (TOCTOU) race condition.

Record
CVE-2021-21615
Updated
2026-11-02
EUVDEUVD-2022-5063 No score

Jenkins 2.275 and LTS 2.263.2 allows reading arbitrary files using the file browser for workspaces and archived artifacts due to a time-of-check to time-of-use (TOCTOU) race condition.

Record
EUVD-2022-5063
Updated
2026-11-03
GitHub AdvisoriesGHSA-qxp6-27gw-99cj 5.3

Time-of-check Time-of-use (TOCTOU) Race Condition in Jenkins

Due to a time-of-check to time-of-use (TOCTOU) race condition, the file browser for workspaces, archived artifacts, and $JENKINS_HOME/userContent/ follows symbolic links to locations outside the directory being browsed in Jenkins 2.275 and LTS 2.263.2.

This allows attackers with Job/Workspace permission and the ability to control workspace contents, e.g., with Job/Configure permission or the ability to change SCM contents, to create symbolic links that allow them to access files outside workspaces using the workspace browser.

This issue is caused by an incorrectly applied fix for SECURITY-1452 / CVE-2021-21602 in the 2021-01-13 security advisory.

Jenkins 2.276, LTS 2.263.3 no longer differentiates the check and the use of symlinks in workspace browsers.

Record
GHSA-qxp6-27gw-99cj
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-367
Updated
2026-11-02
OSVALPINE-CVE-2021-21615 5.3

Jenkins 2.275 and LTS 2.263.2 allows reading arbitrary files using the file browser for workspaces and archived artifacts due to a time-of-check to time-of-use (TOCTOU) race condition.

Record
ALPINE-CVE-2021-21615
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-03
OSV 5.3

Jenkins 2.275 and LTS 2.263.2 allows reading arbitrary files using the file browser for workspaces and archived artifacts due to a time-of-check to time-of-use (TOCTOU) race condition.

Record
CVE-2021-21615
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
Show 4 moreShow less
OSVGHSA-qxp6-27gw-99cj 5.3

Time-of-check Time-of-use (TOCTOU) Race Condition in Jenkins

Due to a time-of-check to time-of-use (TOCTOU) race condition, the file browser for workspaces, archived artifacts, and $JENKINS_HOME/userContent/ follows symbolic links to locations outside the directory being browsed in Jenkins 2.275 and LTS 2.263.2.

This allows attackers with Job/Workspace permission and the ability to control workspace contents, e.g., with Job/Configure permission or the ability to change SCM contents, to create symbolic links that allow them to access files outside workspaces using the workspace browser.

This issue is caused by an incorrectly applied fix for SECURITY-1452 / CVE-2021-21602 in the 2021-01-13 security advisory.

Jenkins 2.276, LTS 2.263.3 no longer differentiates the check and the use of symlinks in workspace browsers.

Record
GHSA-qxp6-27gw-99cj
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-367
Updated
2026-11-02
OSVRHSA-2021:0423 8.0

Red Hat Security Advisory: OpenShift Container Platform 4.6.17 security and packages update

Record
RHSA-2021:0423
CVSS 3.1
8.0 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVRHSA-2021:0429 8.0

Red Hat Security Advisory: OpenShift Container Platform 4.5.33 packages and security update

Record
RHSA-2021:0429
CVSS 3.1
8.0 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVBIT-jenkins-2021-21615 No score

Jenkins LTS 2.263.2 allows reading arbitrary files using the file browser for workspaces and archived artifacts due to a time-of-check to time-of-use (TOCTOU) race condition.

Record
BIT-jenkins-2021-21615
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
org.jenkins-ci.main:jenkins-core
Maven
 through 2.263.2
2.263.3
org.jenkins-ci.main:jenkins-core
Maven
 2.264 to 2.275
2.276
jenkins
Alpine:v3.13
 before 2.281-r0
2.281-r0
jenkins
Bitnami
 before 2.276.0
2.276.0
org.jenkins-ci.main:jenkins-core
Maven
 before 2.263.3, plus listed versions
1.3961.3971.3981.3991.400
Show 45 moreShow less
1.4011.4031.4041.4051.4061.4071.4081.4091.409.11.409.21.409.31.4101.4111.4121.4131.4141.4151.4161.4171.4181.4191.4201.4211.4221.4231.4241.424.11.424.21.424.31.424.41.424.51.424.61.4251.4261.4271.4281.4291.4301.4311.4321.4331.4341.4351.4361.437
2.263.3
org.jenkins-ci.main:jenkins-core
Maven
 2.264 up to 2.276, plus listed versions
2.2652.2662.2672.2682.269
Show 6 moreShow less
2.2702.2712.2722.2732.2742.275
2.276
jenkins
Red Hat:openshift:4.6::el8
 before 0:2.263.3.1612434510-1.el8
0:2.263.3.1612434510-1.el8
conmon
Red Hat:openshift:4.5::el7
 before 2:2.0.21-1.rhaos4.5.el7
2:2.0.21-1.rhaos4.5.el7
jenkins
Red Hat:openshift:4.5::el7
 before 0:2.263.3.1612434332-1.el7
0:2.263.3.1612434332-1.el7
openshift
Red Hat:openshift:4.5::el7
 before 0:4.5.0-202102050524.p0.git.0.9229406.el7
0:4.5.0-202102050524.p0.git.0.9229406.el7
Show 14 moreShow less
Affected packages
PackageAffectedFixed
openshift-ansible
Red Hat:openshift:4.5::el7
 before 0:4.5.0-202102031005.p0.git.0.c6839a2.el7
0:4.5.0-202102031005.p0.git.0.c6839a2.el7
openshift-ansible-test
Red Hat:openshift:4.5::el7
 before 0:4.5.0-202102031005.p0.git.0.c6839a2.el7
0:4.5.0-202102031005.p0.git.0.c6839a2.el7
openshift-clients
Red Hat:openshift:4.5::el7
 before 0:4.5.0-202102051529.p0.git.3612.61b096a.el7
0:4.5.0-202102051529.p0.git.3612.61b096a.el7
openshift-clients-redistributable
Red Hat:openshift:4.5::el7
 before 0:4.5.0-202102051529.p0.git.3612.61b096a.el7
0:4.5.0-202102051529.p0.git.3612.61b096a.el7
openshift-hyperkube
Red Hat:openshift:4.5::el7
 before 0:4.5.0-202102050524.p0.git.0.9229406.el7
0:4.5.0-202102050524.p0.git.0.9229406.el7
conmon
Red Hat:openshift:4.5::el8
 before 2:2.0.21-1.rhaos4.5.el8
2:2.0.21-1.rhaos4.5.el8
machine-config-daemon
Red Hat:openshift:4.5::el8
 before 0:4.5.0-202102050524.p0.git.2594.ff3b8c0.el8
0:4.5.0-202102050524.p0.git.2594.ff3b8c0.el8
openshift
Red Hat:openshift:4.5::el8
 before 0:4.5.0-202102050524.p0.git.0.9229406.el8
0:4.5.0-202102050524.p0.git.0.9229406.el8
openshift-clients
Red Hat:openshift:4.5::el8
 before 0:4.5.0-202102051529.p0.git.3612.61b096a.el8
0:4.5.0-202102051529.p0.git.3612.61b096a.el8
openshift-clients-redistributable
Red Hat:openshift:4.5::el8
 before 0:4.5.0-202102051529.p0.git.3612.61b096a.el8
0:4.5.0-202102051529.p0.git.3612.61b096a.el8
openshift-hyperkube
Red Hat:openshift:4.5::el8
 before 0:4.5.0-202102050524.p0.git.0.9229406.el8
0:4.5.0-202102050524.p0.git.0.9229406.el8
runc
Red Hat:openshift:4.5::el8
 before 0:1.0.0-72.rhaos4.5.giteadfc6b.el8
0:1.0.0-72.rhaos4.5.giteadfc6b.el8
runc-debuginfo
Red Hat:openshift:4.5::el8
 before 0:1.0.0-72.rhaos4.5.giteadfc6b.el8
0:1.0.0-72.rhaos4.5.giteadfc6b.el8
runc-debugsource
Red Hat:openshift:4.5::el8
 before 0:1.0.0-72.rhaos4.5.giteadfc6b.el8
0:1.0.0-72.rhaos4.5.giteadfc6b.el8

History

History
RecordedChangedSources
affected, aliases, referencesOSV
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-21615 is a medium vulnerability (CVSS 5.3) in Jenkins, published January 26, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.91%, the 60th percentile. Fixed in org.jenkins-ci.main:jenkins-core 2.263.3.

References

Show 58 moreShow less
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