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CVE-2026-49981 high CVSS 8.2

Vulnerability in twig/twig (CVE-2026-49981)

Summary

Vulnerability in twig/twig (CVE-2026-49981). Confidential information can be exposed externally. Exploitable via Template. Mitigation: upgrade to 3.27.0 or later.

Original description

The description as published by the source.

Description

The per-template filter, tag and function allow-list check is compiled into the checkSecurity() method of each Template subclass and was invoked once from the constructor, gated by SandboxExtension::isSandboxed($source). Template instances are then cached on the Environment in $loadedTemplates, so the verdict computed at construction time was sticky for the rest of the process.

Any later change of sandbox state on the same Environment left that cached verdict in place: toggling SandboxExtension::enableSandbox()/disableSandbox(), swapping the policy via setSecurityPolicy(), a SourcePolicyInterface decision flip, or simply having a parent, macro or included template pre-instantiated outside the sandbox before a sandboxed render reached it. In all of these cases, the filters, tags and functions used by the affected template kept running with the original (typically empty) check, bypassing the SecurityPolicy allow-list.

Method, property and __toString allow-lists are not affected: they are enforced at every call site at runtime through SandboxExtension::checkMethodAllowed(), checkPropertyAllowed() and ensureToStringAllowed(), which re-read the current state on every call.

Long-lived workers (FrankenPHP, RoadRunner, Symfony Messenger consumers, FPM with hot autoloading) that share a single Environment between sandboxed and non-sandboxed renders are the most exposed: a single non-sandboxed render of a shared layout pre-warms its…

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-2026-49981 has been found in twig/twig.
Attackers can target a specific entry point like Template over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.2/10.
What to do: upgrade twig/twig to 3.27.0 or later.
If unsure, ask your IT team or search "twig/twig CVE-2026-49981" on the vendor's site.

CVE-2026-49981 (twig/twig) — CWE-693 / CVSS v3 8.2
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Template / Environment / SourcePolicyInterface / SecurityPolicy
Patched: 3.27.0 — 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-693) exists in twig/twig. Attackers reach the vulnerable code path via Template without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of twig/twig. Attack surface: Template / Environment / SourcePolicyInterface / SecurityPolicy.

🔥 Severity

Severity: High (CVSS 8.2/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 3.27.0.

🛡️ 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 'twig/twig' . 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 'twig/twig' . | 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 twig/twig 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 twig/twig to 3.27.0

    ステージング環境で 3.27.0 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 twig/twig
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.27.0"}]}]
Packagist twig/twig
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.27.0"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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