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CVE-2026-46639 medium CVSS 6.5

Vulnerability in twig/twig (CVE-2026-46639)

Summary

Vulnerability in twig/twig (CVE-2026-46639). Confidential information can be exposed externally. Exploitable via false. Mitigation: upgrade to 3.26.0 or later.

Original description

The description as published by the source.

Description

The object-destructuring assignment syntax introduced in Twig 3.24.0 generates a call to CoreExtension::getAttribute() with the $sandboxed argument hardcoded to false, regardless of whether a SandboxExtension is active. This permanently disables the sandbox's property and method policy checks for every destructuring expression.

ObjectDestructuringSetBinary::compile() emits:

CoreExtension::getAttribute($this->env, $this->source, ..., \Twig\Template::ANY_CALL, false, false, false, ...);
//                                                                                ^^^^^
//                                                                       sandbox check never runs

Whereas GetAttrExpression::compile() correctly passes $env->hasExtension(SandboxExtension::class).

An attacker with write access to a sandboxed Twig template can read any public property or invoke any public getter on objects passed to the template engine, bypassing SecurityPolicy restrictions. The exploit requires only the {% do %} tag to be in allowedTags, which is a common configuration.

Resolution

The destructuring compiler now forwards the active sandbox flag to getAttribute() so property/method allowlists are enforced.

Credits

Twig would like to thank Anvil Secure in collaboration with Claude and Anthropic Research for reporting and fixing the issue.

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-2026-46639 has been found in twig/twig.
Attackers can target a specific entry point like false over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 6.5/10.
What to do: upgrade twig/twig to 3.26.0 or later.
If unsure, ask your IT team or search "twig/twig CVE-2026-46639" on the vendor's site.

CVE-2026-46639 (twig/twig) — CWE-693 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: false / SandboxExtension / SecurityPolicy / allowedTags
Patched: 3.26.0 — 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 false.

📍 Affected scope

Check the vendor advisory for the affected versions of twig/twig. Attack surface: false / SandboxExtension / SecurityPolicy / allowedTags.

🔥 Severity

Severity: Medium (CVSS 6.5/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 3.26.0.

🛡️ 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 3.26.0

    ステージング環境で 3.26.0 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":"3.26.0"}]}]
Packagist twig/twig
[{"type":"ECOSYSTEM","events":[{"introduced":"3.24.0"},{"fixed":"3.26.0"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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