← Back
CVE-2026-55599
medium
CVSS 5.8
SSRF (Server-Side Request Forgery) in phpseclib/phpseclib (CVE-2026-55599)
Summary
SSRF in phpseclib/phpseclib (CVE-2026-55599). Risk of unauthorized operations or information disclosure. Exploitable via `GET /ssrf`. Mitigation: upgrade to `3.0.54` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-55599** has been found in phpseclib/phpseclib.
Attackers can target a specific entry point like `GET /ssrf` over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.8/10.
What to do: upgrade phpseclib/phpseclib to **3.0.54** or later.
If unsure, ask your IT team or search "phpseclib/phpseclib CVE-2026-55599" on the vendor's site.
CVE-2026-55599 (phpseclib/phpseclib) — CWE-918 / CVSS v3 5.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: GET /ssrf
Patched: `3.0.54` — 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.
❓ What is the problem
**SSRF** (CWE-918) exists in phpseclib/phpseclib. Attackers reach the vulnerable code path via `GET /ssrf` without authentication.
📍 Affected scope
phpseclib/phpseclib — . Attack surface: GET /ssrf.
🔥 Severity
Severity: Medium (CVSS 5.8/10). Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **3.0.54**.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 Detection
Search webserver/proxy logs for unusual `GET /ssrf` requests with malformed payloads or SQL meta-characters. Run `grep -r 'phpseclib/phpseclib' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'phpseclib/phpseclib' . | 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 `phpseclib/phpseclib` を grep し、稼働しているサービス・バージョンを把握する。
-
3Hunt for indicators of compromise detect
grep 'GET /ssrf' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで `GET /ssrf` 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。
-
6Apply patch patch
Upgrade phpseclib/phpseclib to 3.0.54ステージング環境で 3.0.54 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と、Step 3 で見つけた異常検知の続報チェックを含めること。
-
7Post-deployment verification verify
Replay attack against GET /ssrf 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 3 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
composer
phpseclib/phpseclib
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.0.54"}]}]