Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:N) | Network: reachable remotely |
| Attack complexity (AC:L) | Low complexity |
| Attack requirements (AT:N) | No attack requirements |
| Privileges required (PR:L) | Low privileges required |
| User interaction (UI:N) | No user interaction |
| Confidentiality (VC:H) | High confidentiality impact |
| Integrity (VI:L) | Low integrity impact |
| Availability (VA:N) | No availability impact |
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
About Symfony Twig
CVE-2026-48806 affects Symfony Twig, a product from Symfony. Before acting, confirm where Symfony Twig runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: Twig is a template language for PHP. Prior to 3.27.0, ArrayExpression does not guard dynamic mapping keys that are coerced to strings, allowing PHP to invoke __toString() on a Stringable object used as a mapping key without calling SandboxExtension::ensureToStringAllowed(). This issue is fixed in version 3.27.0.
The weakness class is Incorrect Authorization. The permission check exists but gets the answer wrong.
Based on its CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Symfony Twig |
| Affected versions | Twig before 3.27.0 |
| Published | Jul 14, 2026 |
| Last modified | Jul 17, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | security-advisories@github.com |
How to detect it
- Inventory every instance of Symfony Twig and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Symfony Twig named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Symfony Twig to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
- CWE-693 More CVEs with this weakness
- CWE-863: Incorrect Authorization More CVEs with this weakness
Technical References
Frequently asked questions
Related CVEs
Twig is a template language for PHP. Prior to 3.27.0, the sandbox __toString() checks do not fully cover Traversable values passed to join and replace filters or operands evaluated by the in and not in operators, allowing contained Stringable objects to be coerced to strings without consulting the sandbox policy. This issue is fixed in version 3.27.0.
Twig is a template language for PHP. From 3.15.0 until 3.26.0, _self.(<string>) and import-alias dynamic attribute syntax can concatenate an attacker-controlled string into a MacroReferenceExpression name without identifier validation, causing raw PHP to be emitted into the generated template source and executed at template-load time. This issue is fixed in version 3.26.0.
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.
Twig is a template language for PHP. Prior to 3.26.0, Compiler::string() does not escape single quotes when a template name from a {% use %} tag is placed inside a PHP single-quoted string literal, allowing a crafted template name to terminate the string and inject arbitrary PHP expressions into the compiled cache file. This issue is fixed in version 3.26.0.
Twig versions 2.16.x and 3.9.0 through 3.25.x contain a sandbox bypass vulnerability when using a SourcePolicyInterface that allows attackers with template rendering capabilities to pass arbitrary PHP callables to sort, filter, map, and reduce filters. Attackers can exploit the runtime check that fails to use the current template source to bypass sandbox restrictions and execute arbitrary code when the sandbox is enabled through a source policy rather than globally.
Sandbox escape in the Storage: IndexedDB component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
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