Cross-Site Scripting (XSS) in slim/slim (CVE-2026-48157)
Summary
Cross-site scripting in slim/slim (CVE-2026-48157). Risk of unauthorized operations or information disclosure. Exploitable via HttpNotFoundException. Mitigation: upgrade to 4.15.2 or later.
Original description
The description as published by the source.
Slim is a PHP micro framework that enables users to write simple web applications and APIs. In versions 4.4.0 through 4.15, if an application uses HttpException::setTitle() and/or setDescription() to include untrusted/request-derived data in the error title or description (e.g. "No products found matching '{$query}'."), an attacker could inject arbitrary HTML/JavaScript that executes in the victim's browser when they encounter an HTML error page generated by Slim. The vulnerability is present even with displayErrorDetails = false as the unescaped title and description are rendered on this error path. Built-in exceptions (HttpNotFoundException, HttpBadRequestException, etc.) ship plain-text defaults, so a vanilla Slim app with no user code is not exploitable. Only applications that feed untrusted data into setTitle() and/or setDescription() are affected. The issue has been fixed in 4.15.2. If developers are unable to immediately update their applications, they can work around this issue by avoiding passing untrusted/request-derived data into HttpException::setTitle() and setDescription() and using static, plain-text error copy instead.
They should also register a custom error renderer (an ErrorRendererInterface implementation, or a subclass of HtmlErrorRenderer that escapes the title and description) for the HTML media type.
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-2026-48157 has been found in slim/slim.
Attackers can target a specific entry point like HttpNotFoundException over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.1/10.
What to do: upgrade slim/slim to 4.15.2 or later.
If unsure, ask your IT team or search "slim/slim CVE-2026-48157" on the vendor's site.
CVE-2026-48157 (slim/slim) — CWE-79 / CVSS v3 6.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: HttpNotFoundException / HttpBadRequestException / ErrorRendererInterface / HtmlErrorRenderer
Patched: 4.15.2 — 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.
Cross-site scripting (XSS) (CWE-79) exists in slim/slim. Attackers reach the vulnerable code path via HttpNotFoundException without authentication.
Check the vendor advisory for the affected versions of slim/slim. Attack surface: HttpNotFoundException / HttpBadRequestException / ErrorRendererInterface / HtmlErrorRenderer.
Severity: Medium (CVSS 6.1/10). Risk of unauthorized operations or information disclosure.
Update to 4.15.2.
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 'slim/slim' . 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 'slim/slim' . | 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
slim/slim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 slim/slim to 4.15.2ステージング環境で 4.15.2 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
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com