CVE-2026-2415
MEDIUMpretix unsafely evaluates variables in emails
EPSS Exploitation Probability
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
pretix🐍pretix🐍pretixReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Emails sent by pretix can utilize placeholders that will be filled with customer data. For example, when {name} is used in an email template, it will be replaced with the buyer's name for the final email. This mechanism contained two security-relevant bugs:
It was possible to exfiltrate information about the pretix system through specially crafted placeholder names such as {{event.init.code.co_filename}}. This way, an attacker with the ability to control email templates (usually every user of the pretix backend) could retrieve sensitive information from the system configuration, including even database passwords or API keys. pretix does include mechanisms to prevent the usage of such malicious placeholders, however due to a mistake in the code, they were not fully effective for the email subject.
Placeholders in subjects and plain text bodies of emails were wrongfully evaluated twice. Therefore, if the first evaluation of a placeholder again contains a placeholder, this second placeholder was rendered. This allows the rendering of placeholders controlled by the ticket buyer, and therefore the exploitation of the first issue as a ticket buyer. Luckily, the only buyer-controlled placeholder available in pretix by default (that is not validated in a way that prevents the issue) is {invoice_company}, which is very unusual (but not impossible) to be contained in an email subject template. In addition to broadening the attack surface of the first issue, this could theoretically also leak information about an order to one of the attendees within that order. However, we also consider this scenario very unlikely under typical conditions.
Out of caution, we recommend that you rotate all passwords and API keys contained in your pretix.cfg https://docs.pretix.eu/self-hosting/config/ file.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pretix | ≥ 2026.1.0&&< 2026.1.1 | 2026.1.1 |
| 🐍PyPI | pretix | ≥ 2025.10.0&&< 2025.10.2 | 2025.10.2 |
| 🐍PyPI | pretix | all versions | 2025.9.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pretix. 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 pretix to 2026.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-2415 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-2026-2415 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-2026-2415. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-2415 in your dependencies?
O3 detects CVE-2026-2415 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.