CVE-2026-45068
Fix: symfony/symfony@c451448CVE-2026-45068 is a CWE-88 vulnerability in symfony/mailer. O3 Security confirms whether CVE-2026-45068 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Symfony: Argument Injection in SendmailTransport via Dash-Prefixed Recipient Address
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-45068.
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.
Real-World Exposure
symfony/mailer🐘symfony/symfony🐘symfony/mailer🐘symfony/mailer🐘symfony/mailer🐘symfony/symfony🐘symfony/symfony🐘symfony/symfonyReal-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
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/mailer | all versions | 5.4.52 |
| 🐘Packagist | symfony/symfony | all versions | 5.4.52 |
| 🐘Packagist | symfony/mailer | ≥ 6.0.0&&< 6.4.40 | 6.4.40 |
| 🐘Packagist | symfony/mailer | ≥ 7.0.0&&< 7.4.12 | 7.4.12 |
| 🐘Packagist | symfony/mailer | ≥ 8.0.0&&< 8.0.12 | 8.0.12 |
| 🐘Packagist | symfony/symfony | ≥ 6.0.0&&< 6.4.40 | 6.4.40 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/mailer. 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 symfony/mailer to 5.4.52 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45068 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-2026-45068 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-2026-45068. 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-2026-45068 in your dependencies?
O3 detects CVE-2026-45068 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.