SSRF (Server-Side Request Forgery) in flaskbb (CVE-2026-46556)
Summary
SSRF in flaskbb (CVE-2026-46556). Confidential information can be exposed externally. Exploitable via POST /user/settings/user-details.
Original description
The description as published by the source.
###Summary
A Server-Side Request Forgery (SSRF) vulnerability in get_image_info() allows any authenticated user to force the server to send HTTP requests to arbitrary internal endpoints, including cloud metadata services (e.g., AWS 169.254.169.254). This is a blind SSRF with confirmed internal port scanning and internal API triggering capabilities. CVSS 6.5 Medium.
###Details
In flaskbb/utils/helpers.py (line 571), the url parameter is passed directly to requests.get(url, stream=True) without any validation of scheme, host, or IP address.
python# flaskbb/utils/helpers.py:571
def get_image_info(url: str):
r = requests.get(url, timeout=(3.05, 27), stream=True)
Attack chain:
POST /user/settings/user-details (avatar URL)
→ ValidateAvatarURL.validate() # validators.py:103
→ check_image(avatar) # helpers.py:628
→ get_image_info(url) # helpers.py:571
→ requests.get(url) # No domain/IP restriction
Entry points:
/user/settings/user-details (any authenticated user)
/admin/users//edit (admin only)
###PoC
submit.zip
Log in to FlaskBB as any user
Navigate to Settings → User Details
Enter http://169.254.169.254/latest/meta-data/ as the avatar URL
Submit the form
The server sends a GET request to the internal metadata endpoint
Three exploitation channels confirmed:
Server-side request: Captured on mock metadata server
Internal port scan: check_image() return…
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-2026-46556 has been found in flaskbb.
Attackers can target a specific entry point like POST /user/settings/user-details over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 6.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "flaskbb CVE-2026-46556" on the vendor's site.
CVE-2026-46556 (flaskbb) — CWE-918 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /user/settings/user-details
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.
SSRF (CWE-918) exists in flaskbb. Attackers reach the vulnerable code path via POST /user/settings/user-details.
Check the vendor advisory for the affected versions of flaskbb. Attack surface: POST /user/settings/user-details.
Severity: Medium (CVSS 6.5/10). Confidential information can be exposed externally.
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 POST /user/settings/user-details requests with malformed payloads or SQL meta-characters. Run grep -r 'flaskbb' . 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 'flaskbb' . | 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
flaskbbを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /user/settings/user-details' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /user/settings/user-detailsへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Post-deployment verification verify
Replay attack against POST /user/settings/user-details on staging to confirm patch closes the vector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 Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- package github.com
- web github.com
- web github.com
- web security-advisories@github.com