Cross-Site Scripting (XSS) in next (CVE-2026-44581)
Summary
Cross-site scripting in next (CVE-2026-44581). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 16.2.5 or later.
Original description
The description as published by the source.
Impact
App Router applications that rely on CSP nonces can be vulnerable to stored cross-site scripting when deployed behind shared caches. In affected versions, malformed nonce values derived from request headers could be reflected into rendered HTML in an unsafe way, allowing an attacker to poison cached responses and cause script execution for later visitors.
Fix
We now reject or ignore malformed nonce values before they are embedded into HTML and apply stricter nonce sanitization so request-derived nonce data cannot break out of the intended attribute context.
Workarounds
If you cannot upgrade immediately, strip inbound Content-Security-Policy request headers from untrusted traffic.
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-2026-44581 has been found in next.
Risk of unauthorized operations or information disclosure. CVSS score: 4.7/10.
What to do: upgrade next to 16.2.5 or later.
If unsure, ask your IT team or search "next CVE-2026-44581" on the vendor's site.
CVE-2026-44581 (next) — CWE-79 / CVSS v3 4.7
Attack vector: remote (network-reachable) / unauthenticated
Patched: 16.2.5 — apply immediately
Workaround: If you cannot upgrade immediately, strip inbound Content-Security-Policy request headers from untrusted traffic.
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.
Cross-site scripting (XSS) (CWE-79) exists in next.
Check the vendor advisory for the affected versions of next.
Severity: Medium (CVSS 4.7/10). Risk of unauthorized operations or information disclosure.
Update to 16.2.5.
Workaround: If you cannot upgrade immediately, strip inbound Content-Security-Policy request headers from untrusted traffic.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'next' . 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 'next' . | 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
nextを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
If you cannot upgrade immediately, strip inbound `Content-Security-Policy` request headers from untrusted traffic.パッチが適用されるまでの応急処置として、If you cannot upgrade immediately, strip inbound
Content-Security-Policyrequest headers from untrusted traffic. を実施。回避策の副作用 (機能低下) を確認した上で。 -
3Apply patch patch
Upgrade next to 16.2.5ステージング環境で 16.2.5 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。
-
4Post-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
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com