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CVE-2026-48807 critical CVSS 9.1

Vulnerability in twig/twig (CVE-2026-48807)

Summary

Vulnerability in twig/twig (CVE-2026-48807). Confidential information can be exposed externally. Exploitable via Traversable. Mitigation: upgrade to 3.27.0 or later.

Original description

The description as published by the source.

Description

This is a residual bypass of CVE-2026-47732 / GHSA-pr2w-4gpj-cpq4 left after the initial fix for unguarded __toString() calls. It covers two related coercion points that were not caught by the original patch.

Traversable in join and replace filters. SandboxExtension::ensureToStringAllowed() recurses into PHP arrays so that a Stringable object hidden inside an array argument cannot be string-coerced without consulting the security policy. The recursion stops at PHP arrays: a Traversable value passed at the same position is not materialised, so its contents are not policy-checked. CoreExtension::join() and CoreExtension::replace() later materialise such Traversable inputs through self::toArray() and feed them to implode() / strtr(), both of which implicitly call __toString() on contained Stringable objects. The bypass also reproduces when the container implements both Stringable and Traversable: the container's own __toString() is policy-checked, but the elements yielded by getIterator() are not, and the consuming filters still coerce them to string.

in and not in operators. InBinary and NotInBinary compile to CoreExtension::inFilter(), which falls through to PHP's <=> operator when comparing a string with a Stringable object. PHP coerces the object to string via __toString() without the sandbox policy being consulted. Beyond the direct side effect, in can also be used as a content-leak oracle: e…

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-2026-48807 has been found in twig/twig.
Attackers can target a specific entry point like Traversable over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 9.1/10.
What to do: upgrade twig/twig to 3.27.0 or later.
If unsure, ask your IT team or search "twig/twig CVE-2026-48807" on the vendor's site.

CVE-2026-48807 (twig/twig) — CWE-693 / CVSS v3 9.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Traversable / join / replace / Stringable
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 Traversable without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of twig/twig. Attack surface: Traversable / join / replace / Stringable.

🔥 Severity

Severity: Critical (CVSS 9.1/10). 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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