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NVD / CVE Program· CNA jenkins

CVE-2021-21610: Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not implement any restrictions for the URL rendering a formatted preview of markup…

MediumCVSS 6.1 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 24/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.1% (FIRST EPSS); higher than 68.5% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: jenkins (Alpine:v3.12) 2.275-r0; org.jenkins-ci.main:jenkins-core (Maven) 2.275, 2.263.2; jenkins (Red Hat:openshift:3.11::el7) 0:2.263.3.1612433584-1.el7.

Low priority for now. Upgrade to jenkins (Alpine:v3.12) 2.275-r0; org.jenkins-ci.main:jenkins-core (Maven) 2.275, 2.263.2; jenkins (Red Hat:openshift:3.11::el7) 0:2.263.3.1612433584-1.el7 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not implement any restrictions for the URL rendering a formatted preview of markup passed as a query parameter, resulting in a reflected cross-site scripting (XSS) vulnerability if the configured markup formatter does not prohibit unsafe elements (JavaScript) in markup.

Published
Jan 13, 2021
Updated
Jun 16, 2026
EPSS
1.1% · 68th percentile

Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
24 / 40 · 6.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.1%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

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Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
jenkinsjenkins

Limit the impact of XSS

This is a cross-site scripting (XSS) vulnerability. A well-configured Content-Security-Policy doesn't fix it, but greatly reduces its impact. Check your site's CSP and other security headers for free.

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (jenkins). Independent of NVD's CPE analysis and usually ahead of it.

  • Jenkins project Jenkins

    • unspecified and later · up to and including 2.274affected
    • unspecified and later · up to and including LTS 2.263.1affected

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • jenkins jenkinsup to 2.263.1 inclusive
  • jenkins jenkinsup to 2.274 inclusive

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.12jenkinsbefore 2.275-r02.275-r0
Mavenorg.jenkins-ci.main:jenkins-corefrom 2.264 · before 2.2752.275
Mavenorg.jenkins-ci.main:jenkins-corebefore 2.263.22.263.2
Red Hat:openshift:3.11::el7jenkinsbefore 0:2.263.3.1612433584-1.el70:2.263.3.1612433584-1.el7
Red Hat:openshift:3.11::el7jenkins-2-pluginsbefore 0:3.11.1612862361-1.el70:3.11.1612862361-1.el7
Red Hat:openshift:3.11::el7python-rsabefore 0:4.5-3.el70:4.5-3.el7
Red Hat:openshift:3.11::el7python2-rsabefore 0:4.5-3.el70:4.5-3.el7
Red Hat:openshift:4.5::el7conmonbefore 2:2.0.21-1.rhaos4.5.el72:2.0.21-1.rhaos4.5.el7
Red Hat:openshift:4.5::el7jenkinsbefore 0:2.263.3.1612434332-1.el70:2.263.3.1612434332-1.el7
Red Hat:openshift:4.5::el7openshiftbefore 0:4.5.0-202102050524.p0.git.0.9229406.el70:4.5.0-202102050524.p0.git.0.9229406.el7
Red Hat:openshift:4.5::el7openshift-ansiblebefore 0:4.5.0-202102031005.p0.git.0.c6839a2.el70:4.5.0-202102031005.p0.git.0.c6839a2.el7
Red Hat:openshift:4.5::el7openshift-ansible-testbefore 0:4.5.0-202102031005.p0.git.0.c6839a2.el70:4.5.0-202102031005.p0.git.0.c6839a2.el7
Red Hat:openshift:4.5::el7openshift-clientsbefore 0:4.5.0-202102051529.p0.git.3612.61b096a.el70:4.5.0-202102051529.p0.git.3612.61b096a.el7
Red Hat:openshift:4.5::el7openshift-clients-redistributablebefore 0:4.5.0-202102051529.p0.git.3612.61b096a.el70:4.5.0-202102051529.p0.git.3612.61b096a.el7
Red Hat:openshift:4.5::el7openshift-hyperkubebefore 0:4.5.0-202102050524.p0.git.0.9229406.el70:4.5.0-202102050524.p0.git.0.9229406.el7
Red Hat:openshift:4.5::el8conmonbefore 2:2.0.21-1.rhaos4.5.el82:2.0.21-1.rhaos4.5.el8
Red Hat:openshift:4.5::el8machine-config-daemonbefore 0:4.5.0-202102050524.p0.git.2594.ff3b8c0.el80:4.5.0-202102050524.p0.git.2594.ff3b8c0.el8
Red Hat:openshift:4.5::el8openshiftbefore 0:4.5.0-202102050524.p0.git.0.9229406.el80:4.5.0-202102050524.p0.git.0.9229406.el8
Red Hat:openshift:4.5::el8openshift-clientsbefore 0:4.5.0-202102051529.p0.git.3612.61b096a.el80:4.5.0-202102051529.p0.git.3612.61b096a.el8
Red Hat:openshift:4.5::el8openshift-clients-redistributablebefore 0:4.5.0-202102051529.p0.git.3612.61b096a.el80:4.5.0-202102051529.p0.git.3612.61b096a.el8
Red Hat:openshift:4.5::el8openshift-hyperkubebefore 0:4.5.0-202102050524.p0.git.0.9229406.el80:4.5.0-202102050524.p0.git.0.9229406.el8
Red Hat:openshift:4.5::el8runcbefore 0:1.0.0-72.rhaos4.5.giteadfc6b.el80:1.0.0-72.rhaos4.5.giteadfc6b.el8
Red Hat:openshift:4.5::el8runc-debuginfobefore 0:1.0.0-72.rhaos4.5.giteadfc6b.el80:1.0.0-72.rhaos4.5.giteadfc6b.el8
Red Hat:openshift:4.5::el8runc-debugsourcebefore 0:1.0.0-72.rhaos4.5.giteadfc6b.el80:1.0.0-72.rhaos4.5.giteadfc6b.el8

+96

Same product

jenkins: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-23897Jenkins 2.441 and earlier, LTS 2.426.2 and earlier does not disable a feature of its CLI command parser that replaces an '@' character…KEV
    99Now
  • CVE-2017-1000353Jenkins versions 2.56 and earlier as well as 2.46.1 LTS and earlier are vulnerable to an unauthenticated remote code execution.KEV
    99Now
  • CVE-2018-1000861A code execution vulnerability exists in the Stapler web framework used by Jenkins 2.153 and earlier, LTS 2.138.3 and earlier in…KEV
    98Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-21608Jan 13, 2021 · Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not escape button labels in the Jenkins UI, resulting in a cross-site scripting…
    21Monitor
  • ← EarlierCVE-2021-21609Jan 13, 2021 · Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not correctly match requested URLs to the list of always accessible paths, allowing…
    21Monitor
  • Later →CVE-2021-21611Jan 13, 2021 · Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not escape display names and IDs of item types shown on the New Item page…
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:jenkins2.275-r0 · Alpine:v3.12Package registry (OSV)
Maven:org.jenkins-ci.main:jenkins-core2.263.2Package registry (OSV)
Maven:org.jenkins-ci.main:jenkins-core2.275Package registry (OSV)
red hat:conmon2:2.0.21-1.rhaos4.5.el7 · Red Hat:openshift:4.5::el7Package registry (OSV)
red hat:jenkins0:2.263.3.1612434510-1.el8 · Red Hat:openshift:4.6::el8Package registry (OSV)
red hat:machine-config-daemon0:4.5.0-202102050524.p0.git.2594.ff3b8c0.el8 · Red Hat:openshift:4.5::el8Package registry (OSV)
red hat:openshift0:4.5.0-202102050524.p0.git.0.9229406.el7 · Red Hat:openshift:4.5::el7Package registry (OSV)
red hat:openshift-ansible0:4.5.0-202102031005.p0.git.0.c6839a2.el7 · Red Hat:openshift:4.5::el7Package registry (OSV)
red hat:openshift-ansible-test0:4.5.0-202102031005.p0.git.0.c6839a2.el7 · Red Hat:openshift:4.5::el7Package registry (OSV)
red hat:openshift-clients0:4.5.0-202102051529.p0.git.3612.61b096a.el7 · Red Hat:openshift:4.5::el7Package registry (OSV)
red hat:openshift-clients-redistributable0:4.5.0-202102051529.p0.git.3612.61b096a.el7 · Red Hat:openshift:4.5::el7Package registry (OSV)
red hat:openshift-hyperkube0:4.5.0-202102050524.p0.git.0.9229406.el7 · Red Hat:openshift:4.5::el7Package registry (OSV)
red hat:runc0:1.0.0-72.rhaos4.5.giteadfc6b.el8 · Red Hat:openshift:4.5::el8Package registry (OSV)
red hat:runc-debuginfo0:1.0.0-72.rhaos4.5.giteadfc6b.el8 · Red Hat:openshift:4.5::el8Package registry (OSV)
red hat:runc-debugsource0:1.0.0-72.rhaos4.5.giteadfc6b.el8 · Red Hat:openshift:4.5::el8Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

nvd-primary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records