Vulnerability in linkify-it (CVE-2026-48801)
Summary
Vulnerability in linkify-it (CVE-2026-48801). Risk of unauthorized operations or information disclosure. Exploitable via LinkifyIt.prototype.match. Mitigation: upgrade to 5.0.1 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-48801 has been found in linkify-it.
Attackers can target a specific entry point like LinkifyIt.prototype.match over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade linkify-it to 5.0.1 or later.
If unsure, ask your IT team or search "linkify-it CVE-2026-48801" on the vendor's site.
CVE-2026-48801 (linkify-it) — CWE-1333 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: LinkifyIt.prototype.match / tail / lastIndex / email_fuzzy
Patched: 5.0.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-1333) exists in linkify-it. Attackers reach the vulnerable code path via LinkifyIt.prototype.match without authentication.
Check the vendor advisory for the affected versions of linkify-it. Attack surface: LinkifyIt.prototype.match / tail / lastIndex / email_fuzzy.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 5.0.1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'linkify-it' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'linkify-it' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
linkify-itを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade linkify-it to 5.0.1ステージング環境で 5.0.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Ubuntu UBUNTU-CVE-2026-48801 node-markdown-it
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- ATLASSIAN JSDSERVER-16766
- package github.com
- patch github.com
- web github.com