Authentication Bypass in Flask-HTTPAuth (CVE-2026-34531)
Summary
Authentication bypass in Flask-HTTPAuth (CVE-2026-34531). Data can be tampered with by attackers. Exploitable via token. Mitigation: upgrade to 4.8.1 or later.
Original description
The description as published by the source.
Flask-HTTPAuth provides Basic, Digest and Token HTTP authentication for Flask routes. Prior to version 4.8.1, in a situation where the client makes a request to a token protected resource without passing a token, or passing an empty token, Flask-HTTPAuth would invoke the application's token verification callback function with the token argument set to an empty string. If the application had any users in its database with an empty string set as their token, then it could potentially authenticate the client request against any of those users. This issue has been patched in version 4.8.1.
Source: NIST National Vulnerability Database 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-2026-34531 has been found in Flask-HTTPAuth.
Attackers can target a specific entry point like token over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 6.5/10.
What to do: upgrade Flask-HTTPAuth to 4.8.1 or later.
If unsure, ask your IT team or search "Flask-HTTPAuth CVE-2026-34531" on the vendor's site.
CVE-2026-34531 (Flask-HTTPAuth) — CWE-287 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: token / NULL
Patched: 4.8.1 — 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.
Authentication bypass (CWE-287) exists in Flask-HTTPAuth. Attackers reach the vulnerable code path via token without authentication.
Check the vendor advisory for the affected versions of Flask-HTTPAuth. Attack surface: token / NULL.
Severity: Medium (CVSS 6.5/10). Data can be tampered with by attackers.
Update to 4.8.1.
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 'Flask-HTTPAuth' . 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 'Flask-HTTPAuth' . | 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
Flask-HTTPAuth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 Flask-HTTPAuth to 4.8.1ステージング環境で 4.8.1 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
- Debian DEBIAN-CVE-2026-34531 python-flask-httpauth Fixed in: 3.2.4-3.1+deb11u1
- Ubuntu UBUNTU-CVE-2026-34531 python-flask-httpauth
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- patch github.com
- web github.com
- web lists.debian.org
- web github.com