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Fencer Vulns
medium 5.3

CVE-2022-21670 json

Uncontrolled Resource Consumption in markdown-it

published 2022-01-10 4 y ago modified 2026-06-17 4 mo ago also GHSA-6vfc-qv3f-vr6c , EUVD-2022-0488

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

markdown-it is a Markdown parser. Prior to version 1.3.2, special patterns with length greater than 50 thousand characterss could slow down the parser significantly. Users should upgrade to version 12.3.2 to receive a patch. There are no known workarounds aside from upgrading.

Patch / fix

  • npm markdown-it 12.3.2
  • node-markdown-it Debian 14, Debian 13, Debian 12 10.0.0+dfsg-6

debian advisories DEBIAN-CVE-2022-21670

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

2.36% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/markdown-it/markdown-it/security/advisories/GHSA-6vfc-qv3f-vr6c referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
npm markdown-it
<12.3.2
12.3.2

Affected products

  • markdown-it markdown-it

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-1333 Inefficient Regular Expression Complexity

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.