Vulnerability in Haxx (CVE-2026-6276)
Summary
Vulnerability in Haxx (CVE-2026-6276). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
Using libcurl, when a custom Host: header is first set for an HTTP request
and a second request is subsequently done using the same easy handle but
without the custom Host: header set, the second request would use stale
information and pass on cookies meant for the first host in the second
request. Leak them.
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-2026-6276 has been found in Haxx.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Haxx CVE-2026-6276" on the vendor's site.
CVE-2026-6276 (Haxx) — CWE-319 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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-319) exists in Haxx.
Check the vendor advisory for the affected versions of Haxx.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
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 'Haxx' . 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 'Haxx' . | 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
Haxxを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-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。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Alpine Linux ALPINE-CVE-2026-6276 curl Fixed in: 8.20.0-r0
- BellSoft Alpaquita BELL-CVE-2026-6276 curl Fixed in: 8.20.0-r0
- Debian DEBIAN-CVE-2026-6276 curl
- Ubuntu UBUNTU-CVE-2026-6276 curl Fixed in: 7.81.0-1ubuntu1.24
References
- web nvd.nist.gov
- web hackerone.com
- web curl.se
- web curl.se
- web openwall.com
- web github.com