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CVE-2026-49214 medium CVSS 5.3

Vulnerability in guzzlehttp/psr7 (CVE-2026-49214)

Summary

Vulnerability in guzzlehttp/psr7 (CVE-2026-49214). Risk of unauthorized operations or information disclosure. Exploitable via Uri. Mitigation: upgrade to 2.10.2 or later.

Original description

The description as published by the source.

Impact

guzzlehttp/psr7 did not reject ASCII control characters, whitespace, or DEL in first-party URI host components. The issue requires a PSR-7 request to be serialized into a raw HTTP/1.x message, for example with GuzzleHttp\Psr7\Message::toString() or an equivalent custom serializer. Creating a Uri, Request, or other PSR-7 object alone is not sufficient. The malformed host must be copied into the serialized Host header without further validation.

A vulnerable flow is:

  1. An application accepts a user-controlled URL.
  2. The URL is used to construct a PSR-7 Uri or Request.
  3. The host component contains CRLF or another header-unsafe character.
  4. The request is serialized into a raw HTTP/1.x message without an explicit Host header.
  5. The host is copied into the serialized Host header.
  6. The serialized request is written to the network or otherwise processed by software that does not independently reject the malformed host.

In that flow, an attacker can cause the serialized request to contain additional attacker-controlled header lines. For example, a host containing "\r\nX-Injected: yes" can cause the generated Host header to span multiple HTTP header lines.

This is not the normal request-sending path used by guzzlehttp/guzzle. Applications using guzzlehttp/psr7 only through Guzzle's standard HTTP client APIs are not expected to be affected. Applications are most likely to be affected when they manually serialize PSR-7 requests, forward r…

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-2026-49214 has been found in guzzlehttp/psr7.
Attackers can target a specific entry point like Uri over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade guzzlehttp/psr7 to 2.10.2 or later.
If unsure, ask your IT team or search "guzzlehttp/psr7 CVE-2026-49214" on the vendor's site.

CVE-2026-49214 (guzzlehttp/psr7) — CWE-20 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Uri / Request / Host
Patched: 2.10.2 — 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

A vulnerability (CWE-20) exists in guzzlehttp/psr7. Attackers reach the vulnerable code path via Uri without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of guzzlehttp/psr7. Attack surface: Uri / Request / Host.

🔥 Severity

Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 2.10.2.

🛡️ 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 request patterns matching this CVE's known IOCs. Run grep -r 'guzzlehttp/psr7' . 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

  1. 1
    Identify exposure identify 
    grep -r 'guzzlehttp/psr7' . | 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 guzzlehttp/psr7 を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade guzzlehttp/psr7 to 2.10.2

    ステージング環境で 2.10.2 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。

  3. 3
    Post-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

composer guzzlehttp/psr7
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.10.2"}]}]
Packagist guzzlehttp/psr7
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.10.2"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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