Vulnerability in phpbb/phpbb (CVE-2026-29199)
Summary
Vulnerability in phpbb/phpbb (CVE-2026-29199). Confidential information can be exposed externally. Exploitable via Host header. Mitigation: upgrade to 4.0.0-a2 or later.
Original description
The description as published by the source.
phpBB before 3.3.16 is vulnerable to Host Header Injection that can lead to password rest link poisoning. When force_server_vars is disabled, the servers hostname may be extracted from the HTTP Host header which is used to generate the password reset link URL. An attacker who can manipulate the Host header (e.g. through misconfigured host setup or missing header validation by the webserver) can cause password reset emails to contain a link pointing to an attacker-controlled domain, potentially leading to account takeover.
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-2026-29199 has been found in phpbb/phpbb.
Attackers can target a specific entry point like Host header over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.1/10.
What to do: upgrade phpbb/phpbb to 4.0.0-a2 or later.
If unsure, ask your IT team or search "phpbb/phpbb CVE-2026-29199" on the vendor's site.
CVE-2026-29199 (phpbb/phpbb) — CWE-640 / CVSS v3 8.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: Host header
Patched: 4.0.0-a2 — 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-640) exists in phpbb/phpbb. Attackers reach the vulnerable code path via Host header without authentication.
Check the vendor advisory for the affected versions of phpbb/phpbb. Attack surface: Host header.
Severity: High (CVSS 8.1/10). Confidential information can be exposed externally.
Update to 4.0.0-a2.
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 'phpbb/phpbb' . 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
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1Identify exposure identify
grep -r 'phpbb/phpbb' . | 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
phpbb/phpbb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 phpbb/phpbb to 4.0.0-a2ステージング環境で 4.0.0-a2 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
References
- advisory nvd.nist.gov
- package github.com
- web hackerone.com
- web blog.phpbb.com
- web phpbb.com
- web github.com