CVE-2021-28834

mediumpriority · track · 40EPSS 0.027 · 86 %ileDEEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

2.70% (86th) EPSS

CVSS 6.8 · medium

Is it mine?

13 products

Check your exposure

Who says so?

6 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

EPSS · scored 2026-10-27

Kramdown before 2.3.1 does not restrict Rouge formatters to the Rouge::Formatters namespace, and thus arbitrary classes can be instantiated.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

Fixedruby4.0-rubygem-kramdown-0:2.4.0-1.17.aarch64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedruby4.0-rubygem-kramdown-0:2.4.0-1.17.ppc64le as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedruby4.0-rubygem-kramdown-0:2.4.0-1.17.s390x as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Fixedruby4.0-rubygem-kramdown-0:2.4.0-1.17.x86_64 as component of openSUSE Tumbleweedsuse_csaf
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".

cvss

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 6.8–9.8

v2.06.8mediumAV:N/AC:M/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 6.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.19.8criticalAV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · OSV

v3.19criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · SUSE Product Security

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-470USCWE-94US

affected products (13)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
Thomas Leitner Kramdown1.16 → 2.3.1fstec_bduRU
АО «НППКТ» ОСОН ОСнова Оnyx≤ 2.1fstec_bduRU
ООО «РусБИТех-Астра» Astra Linux Special Edition≤ 1.7fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 8fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 9fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 10fstec_bduRU
debian debian linux= 10.0nvdUScpe:2.3:o:debian:debian_linux:*:*:*:*:*:*:*:*
fedoraproject fedora= 32nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
fedoraproject fedora= 33nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
fedoraproject fedora= 34nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
kramdown project kramdown< 2.3.1nvdUScpe:2.3:a:kramdown_project:kramdown:*:*:*:*:*:*:*:*
RubyGems kramdown1.16.0 → 2.3.1osvUSpkg:gem/kramdown

advisories (2)

Vendor and ecosystem advisories describing this.

openSUSE-SU-2026:10352-1ruby4.0-rubygem-kramdown-2.4.0-1.17 on GA media2026-03-13csaf · suse_csafDE
ruby4.0-rubygem-kramdown-2.4.0-1.17 on GA media
GHSA-52p9-v744-mwjjRemote code execution in Kramdown2021-03-29ghsa · osvUS
Kramdown before 2.3.1 does not restrict Rouge formatters to the Rouge::Formatters namespace, and thus arbitrary classes can be instantiated.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu nvd osv suse_csaf NVD CVE.org MITRE

published 2021-03-19modified 2026-06-17

references (24)

External citations — patches, advisories, analysis.

scry

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