CVE-2026-46633: Twig PHP Code Injection Vulnerability

CRITICAL
Advisory Identifier: GHSA-7p85-w9px-jpjp
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CWE-94
Published
Advisory Summary

CVE-2026-46633 is a CRITICAL php code injection vulnerability (CWE-94: Improper Control of Generation of Code ('Code Injection')) affecting Twig libraries in the Packagist ecosystem. The issue involves php code injection via `{% use %}` template name. Remediation is available by upgrading affected packages to version 3.26.0.

CVE-2026-46633 at a Glance

CVE Identifier CVE-2026-46633
GHSA Identifier GHSA-7p85-w9px-jpjp
Severity CRITICAL
CVSS v3.1 Base Score N/A
CWE Classification CWE-94: Improper Control of Generation of Code ('Code Injection')
Affected Product Twig
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-46633

To remediate this vulnerability, upgrade all affected Twig dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

twig/twig fixed: 3.26.0 
Upgrade twig/twig to 3.26.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for twig/twig

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-46633, inspect your project dependencies for Twig:

inspect dependencies for twig/twig

Analyze the terminal output to locate any version of Twig in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.26.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-94: Improper Control of Generation of Code ('Code Injection'), where the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. In Twig, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Description `Compiler::string()` escapes `"`, `$`, `\`, NUL and TAB when generating PHP double-quoted string literals, but does not escape single quotes. In `ModuleNode::compileConstructor()`, the template name from a `{% use %}` tag is compiled via `subcompile()` -> `string()` and placed inside a surrounding PHP single-quoted string literal. A template name containing a single quote terminates that surrounding string early, allowing arbitrary PHP expressions to be injected into the compiled cache file. The injected code executes within the PHP process when the cache file is first loaded, bypassing the Twig sandbox entirely and achieving remote code execution. `SecurityPolicy` unconditionally allows `{% use %}` regardless of the configured `allowedTags`, so this primitive is reachable from sandboxed templates as well. ### Resolution `Compiler::string()` now also escapes single quotes so that template names placed inside single-quoted PHP literals can no longer break out of the surrounding context. ### Credits Twig would like to thank Anvil Secure in collaboration with Claude and Anthropic Research for reporting the issue and providing the fix.

CVE-2026-46633 Affected Twig Versions

1 component(s)
Fixed Versions:
3.26.0
Product / Package Ecosystem Affected Versions Fixed Version
twig/twig
 Packagist
< 3.26.0
3.26.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/twigphp/Twig/security/advisories/GHSA-7p85-w9px-jpjp
Twig Source Repository REPOSITORY
https://github.com/FriendsOfPHP/security-advisories/blob/master/twig/twig/CVE-2026-46633.yaml
Twig Source Repository REPOSITORY
https://github.com/twigphp/Twig
symfony.com/cve-2026-46633 WEB
https://symfony.com/cve-2026-46633

Frequently Asked Questions

What is CVE-2026-46633?
CVE-2026-46633 is a security vulnerability in Twig involving PHP code injection via `{% use %}` template name under CWE-94: Improper Control of Generation of Code ('Code Injection').
Which Twig versions are affected?
Affected versions include releases prior to 3.26.0 across affected packages: twig/twig.
What version fixes CVE-2026-46633?
Upgrading to 3.26.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is twig/twig affected?
Yes, twig/twig is affected in releases prior to 3.26.0. Upgrade your dependency to 3.26.0 or later.
What CWE is associated with CVE-2026-46633?
CVE-2026-46633 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).
How can I check Packagist dependencies for CVE-2026-46633?
Run the dependency tree command: 'inspect dependencies for twig/twig'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7p85-w9px-jpjp",
  "modified" : "2026-05-21T21:24:53Z",
  "published" : "2026-05-21T21:24:53Z",
  "aliases" : [ "CVE-2026-46633" ],
  "summary" : "Twig: PHP code injection via `{% use %}` template name",
  "details" : "### Description\n\n`Compiler::string()` escapes `\"`, `$`, `\\`, NUL and TAB when generating PHP double-quoted string literals, but does not escape single quotes. In `ModuleNode::compileConstructor()`, the template name from a `{% use %}` tag is compiled via `subcompile()` -> `string()` and placed inside a surrounding PHP single-quoted string literal. A template name containing a single quote terminates that surrounding string early, allowing arbitrary PHP expressions to be injected into the compiled cache file.\n\nThe injected code executes within the PHP process when the cache file is first loaded, bypassing the Twig sandbox entirely and achieving remote code execution. `SecurityPolicy` unconditionally allows `{% use %}` regardless of the configured `allowedTags`, so this primitive is reachable from sandboxed templates as well.\n\n### Resolution\n\n`Compiler::string()` now also escapes single quotes so that template names placed inside single-quoted PHP literals can no longer break out of the surrounding context.\n\n### Credits\n\nTwig would like to thank Anvil Secure in collaboration with Claude and Anthropic Research for reporting the issue and providing the fix.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "twig/twig"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.26.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/twigphp/Twig/security/advisories/GHSA-7p85-w9px-jpjp"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/twig/twig/CVE-2026-46633.yaml"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/twigphp/Twig"
  }, {
    "type" : "WEB",
    "url" : "https://symfony.com/cve-2026-46633"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-94" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-21T21:24:53Z",
    "nvd_published_at" : null
  }
}