What is CVE-2026-46634?

CVE-2026-46634 is a critical-severity vulnerability in Symfony Twig, classified under Protection Mechanism Failure. CVSS score: 9.8/10. Published 2026-07-14.

How severe is CVE-2026-46634?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Symfony Twig

CVE-2026-46634

Twig is a template language for PHP. From 3.9.0 until 3.26.0, template_from_string() compiles an inner template under a synthesized __string_template__<hash> name that can fall outside a SourcePolicyInterface sandbox decision, allowing a sandboxed template that can call template_from_string and include to render an inner template without security policy enforcement. This issue is fixed in version 3.26.0.

Published 2026-07-14 · last modified 2026-07-29.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (48.9th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Symfony Twig
Twigphp Twig — versions >= 3.9.0, < 3.26.0

Weakness classification (CWE)

CWE-693 — Protection Mechanism Failure

References

github.com/twigphp/Twig/security/advisories/GHSA-24x9-r6q4-q93w (Vendor Advisory)
github.com/twigphp/Twig/commit/1cde8f2b62463f85d47995fc25f8241cb409d915 (Patch)
github.com/twigphp/Twig/releases/tag/v3.26.0 (Release Notes)

Frequently asked questions

What is CVE-2026-46634?: CVE-2026-46634 is a critical-severity vulnerability in Symfony Twig, classified under Protection Mechanism Failure. CVSS score: 9.8/10. Published 2026-07-14.
How severe is CVE-2026-46634?: Critical severity. CVSS v3 base score is 9.8 out of 10.