How severe is CVE-2026-31819?

No CVSS score has been assigned to CVE-2026-31819 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-31819?

CVE-2026-31819 affects the following packages: sylius/sylius (Packagist), sylius/sylius (Packagist), sylius/sylius (Packagist), sylius/sylius (Packagist), sylius/sylius (Packagist), sylius/sylius (Packagist), sylius/sylius (Packagist), sylius/sylius (Packagist), and 1 more. Ecosystems affected: Packagist.

How do I fix CVE-2026-31819?

Update sylius/sylius to 1.9.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-31819 is resolved across your whole dependency graph.

How do I detect CVE-2026-31819 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sylius/sylius. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-31819 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-31819?

O3 pinpoints whether CVE-2026-31819 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-31819 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-31819 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-31819?

CVE-2026-31819 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 7th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2026-31819 published, and has it been updated?

CVE-2026-31819 was published on March 10, 2026 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-31819: Sylius has an Open Redirect via Referer Header

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk7th percentile+0.12%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

9 pkgs affected

🐘sylius/sylius🐘sylius/sylius🐘sylius/sylius🐘sylius/sylius🐘sylius/sylius🐘sylius/sylius🐘sylius/sylius🐘sylius/sylius+1 more

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Sylius is an Open Source eCommerce Framework on Symfony. CurrencySwitchController::switchAction(), ImpersonateUserController::impersonateAction() and StorageBasedLocaleSwitcher::handle() use the HTTP Referer header directly when redirecting. The attack requires the victim to click a legitimate application link placed on an attacker-controlled page. The browser automatically sends the attacker's site as the Referer, and the application redirects back to it. This can be used for phishing or credential theft, as the redirect originates from a trusted domain. The severity varies by endpoint; public endpoints require no authentication and are trivially exploitable, while admin-only endpoints require an authenticated session but remain vulnerable if an admin follows a link from an external source such as email or chat. The issue is fixed in versions: 1.9.12, 1.10.16, 1.11.17, 1.12.23, 1.13.15, 1.14.18, 2.0.16, 2.1.12, 2.2.3 and above.

Affected Packages

9 total 9 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`sylius/sylius`	all versions	1.9.12
🐘Packagist	`sylius/sylius`	≥ 1.10.0&&< 1.10.16	1.10.16
🐘Packagist	`sylius/sylius`	≥ 1.11.0&&< 1.11.17	1.11.17
🐘Packagist	`sylius/sylius`	≥ 1.12.0&&< 1.12.23	1.12.23
🐘Packagist	`sylius/sylius`	≥ 1.13.0&&< 1.13.15	1.13.15
🐘Packagist	`sylius/sylius`	≥ 1.14.0&&< 1.14.18	1.14.18

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sylius/sylius. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update sylius/sylius to 1.9.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-31819 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-31819 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-31819. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Sylius is an Open Source eCommerce Framework on Symfony. CurrencySwitchController::switchAction(), ImpersonateUserController::impersonateAction() and StorageBasedLocaleSwitcher::handle() use the HTTP Referer header directly when redirecting. The attack requires the victim to click a legitimate application link placed on an attacker-controlled page. The browser automatically sends the attacker's site as the Referer, and the application redirects back to it. This can be used for phishing or credential theft, as the redirect originates from a trusted domain. The severity varies by endpoint; publi

O3 Security · Impact-Aware SCA

Is CVE-2026-31819 in your dependencies?

O3 detects CVE-2026-31819 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2026-31819