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:N) | No privileges required |
| User interaction (UI:N) | No user interaction |
| Confidentiality (VC:H) | High confidentiality impact |
| Integrity (VI:N) | No integrity impact |
| Availability (VA:N) | No availability impact |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/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 Sensiolabs Symfony
CVE-2026-45071 affects Sensiolabs Symfony, a product from Sensiolabs. Before acting, confirm where Sensiolabs Symfony 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: Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Crawler::addXmlContent() set DOMDocument::$validateOnParse = true before loadXML(), re-enabling external entity resolution and allowing attacker-supplied XML to expand file:// entities such as local files. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
The weakness class is XML External Entity. XML parsing can be abused to read files or reach internal systems.
Based on its CVSS vector, the flaw can be reached over the network, needs no login, 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 | Sensiolabs Symfony |
| Affected versions | Symfony before 5.4.52; Symfony from 6.0.0 before 6.4.40; Symfony from 7.0.0 before 7.4.12; Symfony from 8.0.0 before 8.0.12 |
| Published | Jul 14, 2026 |
| Last modified | Jul 15, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | security-advisories@github.com |
How to detect it
- Inventory every instance of Sensiolabs Symfony 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 Sensiolabs Symfony 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 Sensiolabs Symfony 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-611: XML External Entity More CVEs with this weakness
Technical References
Frequently asked questions
Related CVEs
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.53, 6.4.41, 7.4.13, and 8.0.13, DefaultAuthenticationFailureHandler honored the request-supplied _failure_path parameter when failure_forward: true was enabled, allowing an unauthenticated failing login request to dispatch a subrequest to access_control-protected GET routes that skipped firewall listeners. This issue is fixed in versions 5.4.53, 6.4.41, 7.4.13, and 8.0.13.
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, SendmailTransport in -t mode appended recipient addresses to the sendmail command line without a -- end-of-options separator, allowing an address beginning with - to be interpreted as a sendmail command-line option instead of an address. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 5.4.46 until 5.4.52, 6.4.40, 7.4.12, and 8.0.12, the CVE-2024-50340 fix gated runtime argv parsing on empty($_GET), but parse_str() and the web SAPI can disagree, allowing a crafted query string to leave $_GET empty while $_SERVER['argv'] still carries attacker-controlled --env or --no-debug flags that change APP_ENV or APP_DEBUG. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Yaml\Parser::cleanup() used regular expressions with overlapping quantifiers for YAML directive, comment, and document marker cleanup, allowing crafted input to make parsing hang for an arbitrarily long time. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Yaml\Parser resolved YAML collection aliases recursively, allowing a small untrusted YAML input to expand into a multi-gigabyte structure and exhaust memory. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, when the parser is exposed to attacker-controlled input, deeply nested mappings or sequences cause both the block-level (Parser::parseBlock()) and inline (Inline::parseSequence() / Inline::parseMapping()) parsers to recurse without a depth limit. A crafted document exhausts the PHP stack and crashes the worker. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
Earn your free CTEM certification.
Learn to scope, prioritize, validate and mobilize fixes for CVEs like CVE-2026-45071 with a free CTEM certification.
Beginner / Practitioner / Program Leader
Explore certifications