Vulnerability in guzzlehttp/psr7 (CVE-2026-59882)
Summary
Vulnerability in guzzlehttp/psr7 (CVE-2026-59882). Risk of unauthorized operations or information disclosure. Exploitable via SERVER_NAME. Mitigation: upgrade to 2.12.3 or later.
Original description
The description as published by the source.
guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Prior to 2.12.3, Uri::assertValidHost() does not reject URI host components containing authority delimiters, embedded ports, or malformed IPv6 brackets, allowing Uri::getHost() to disagree with the URI authority used for security or routing decisions. This issue is fixed in version 2.12.3.
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-2026-59882 has been found in guzzlehttp/psr7.
Attackers can target a specific entry point like SERVER_NAME over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.2/10.
What to do: upgrade guzzlehttp/psr7 to 2.12.3 or later.
If unsure, ask your IT team or search "guzzlehttp/psr7 CVE-2026-59882" on the vendor's site.
CVE-2026-59882 (guzzlehttp/psr7) — CWE-20 / CVSS v3 4.2
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: SERVER_NAME / SERVER_ADDR / Uri / Host
Patched: 2.12.3 — apply immediately
Workaround: If you cannot upgrade immediately, validate and normalize host values before you build or modify a Uri from untrusted input, and do not treat Uri::getHost() as a trust boundary for a host you have not independently checked.
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 SERVER_NAME without authentication.
Check the vendor advisory for the affected versions of guzzlehttp/psr7. Attack surface: SERVER_NAME / SERVER_ADDR / Uri / Host.
Severity: Medium (CVSS 4.2/10). Risk of unauthorized operations or information disclosure.
Update to 2.12.3.
Workaround: If you cannot upgrade immediately, validate and normalize host values before you build or modify a Uri from untrusted input, and do not treat Uri::getHost() as a trust boundary for a host you have not independently checked.
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 temporary workaround mitigate
If you cannot upgrade immediately, validate and normalize host values before you build or modify a `Uri` from untrusted input, and do not treat `Uri::getHost()` as a trust boundary for a host you have not independently checked.パッチが適用されるまでの応急処置として、If you cannot upgrade immediately, validate and normalize host values before you build or modify a
Urifrom untrusted input, and do not treatUri::getHost()as a trust boundary for a host you have not independently checked. を実施。回避策の副作用 (機能低下) を確認した上で。 -
3Apply patch patch
Upgrade guzzlehttp/psr7 to 2.12.3ステージング環境で 2.12.3 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。
-
4Post-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-2026-59882 php-guzzlehttp-psr7
- Ubuntu UBUNTU-CVE-2026-59882 php-guzzlehttp-psr7
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- patch github.com
- patch github.com
- web github.com
- web github.com