CVE-2026-48801: linkify-it: Quadratic algorithmic complexity in LinkifyIt#match scan loop
Vulnerability summary
CVE-2026-48801 is a high (CVSS 8.7) vulnerability in markdown-it linkify-it. EPSS estimates a 0.39% chance of exploitation in the next 30 days, higher than 33.6% of scored vulnerabilities. 1 public exploit is recorded.
Public exploit (GitHub, Date unknown)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 3 · Related 1Timeline
- 14-07-2026PublishedVulnerability first disclosed.
- 15-07-2026Last modifiedVulnerability information updated.
Description
linkify-it is a links recognition library with full Unicode support. Prior to 5.0.1, LinkifyIt.prototype.match, the package's primary public API, has O(N²) algorithmic complexity for inputs containing many fuzzy links or emails because the JavaScript-level scan loop re-slices input and re-runs unanchored regex searches on progressively shorter tails. Any service that synchronously renders untrusted Markdown with linkify:true on a request hot path can inherit a worker-process denial of service triggerable by a tens-of-KB request body. This issue is fixed in version 5.0.1.
CVSS metrics
8 scores · 6 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- OSV · WolfiEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- OSV · NpmEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- OSV · ChainguardEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- NVDNIST8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.39%
Chance of exploitation in the next 30 days
Percentile
34%
Versus all other CVEs
30-day change
Decrease -0.12 pp
From 0.52% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundLinkify It
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Chainguard34 products
- argo-workflows-ui-3.6< 3.6.19-r7
- gitlab-rails-ce-18.1< 18.1.6-r24
- gitlab-rails-ce-18.10All versions (No fix recorded)
- gitlab-rails-ce-18.11< 18.11.6-r10
- gitlab-rails-ce-18.5All versions (No fix recorded)
Markdown-it1 product
- linkify-it< 5.0.1
Npm1 product
- linkify-it< 5.0.1
Ubuntu1 product
- node-markdown-itAll versions (No fix recorded)
Wolfi1 product
- opensearch-dashboards-3-dashboards-observability< 3.7.0-r5
5 vendors · 38 products
References
7 links- github.com/markdown-it/linkify-it/security/advisories/GHSA-22p9-wv53-3rq4X Refsource CONFIRMREPORTAdvisoryWEBExploitVendor Advisory
- github.com/markdown-it/linkify-it/commit/6be6d15e0641bf1daeaa977d500cabc743166159X Refsource MISCREPORTFIXPatch
