Vulnerability in guzzlehttp/psr7 (CVE-2026-48998)
Summary
Vulnerability in guzzlehttp/psr7 (CVE-2026-48998). Risk of unauthorized operations or information disclosure. Exploitable via Host header. Mitigation: upgrade to 2.10.2 or later.
Original description
The description as published by the source.
guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Versions prior to 2.10.2 contain improper Host header validation when parsing raw HTTP request messages and when deriving a server request URI from server variables. An attacker can provide a malformed Host header containing URI authority delimiters, such as trusted.example@evil.example. When the Host value is used to construct a URI, the malformed value can be reinterpreted as URI userinfo and host. This can cause the PSR-7 request URI host to differ from the original Host header value. Applications are affected if they parse attacker-controlled raw HTTP requests with GuzzleHttp\Psr7\Message::parseRequest() or the legacy 1.x GuzzleHttp\Psr7\parse_request() function, or if they build server requests from attacker-controlled server variables, then rely on the resulting URI host for routing, allow-list checks, or forwarding decisions. In affected forwarding or gateway scenarios, this may cause requests or credentials to be sent to an unintended host. The issue is patched in 2.10.2. 1.x is end-of-life and will not receive a patch. Some workarounds are available. Validate the Host header as uri-host [ ":" port ] before calling Message::parseRequest() or legacy parse_request() on untrusted HTTP request data, or before deriving routing and forwarding decisions from a parsed request URI. Reject Host values containing userinfo, path, query, or fragment delimiters.
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-2026-48998 has been found in guzzlehttp/psr7.
Attackers can target a specific entry point like Host header 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-2026-48998" on the vendor's site.
CVE-2026-48998 (guzzlehttp/psr7) — CWE-20 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Host header / Host / evil.example
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.
A vulnerability (CWE-20) exists in guzzlehttp/psr7. Attackers reach the vulnerable code path via Host header without authentication.
Check the vendor advisory for the affected versions of guzzlehttp/psr7. Attack surface: Host header / Host / evil.example.
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.
Update to 2.10.2.
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 '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
-
1Identify 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。 -
2Apply 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。
-
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-2026-48998 php-guzzlehttp-psr7
- Ubuntu UBUNTU-CVE-2026-48998 php-guzzlehttp-psr7
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com