CVE-2026-45304: 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 resolve

highCVSS 7.5CVE-2026-45304

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.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: high — CVSS 7.5
Published: 2026-07-14
Last updated: 2026-07-15
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-45304

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-453040.80% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 53% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-45304	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

medium[UPDATE] [medium] Zabbix: Multiple Vulnerabilitiescert-bund

Recent advisories for Symfony is a

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumCVE-2026-49216: Symfony UX is a JavaScript ecosystem for Symfony. From 2.2.0 until 2.36.0 and 3.1.0, the Stimu…nvd · 2026-07-17
mediumCVE-2026-49215: Symfony UX is a JavaScript ecosystem for Symfony. From 2.22.0 until 2.36.0 and 3.1.0, Symfony\…nvd · 2026-07-17
highCVE-2026-49212: Symfony UX is a JavaScript ecosystem for Symfony. From 2.8.0 until 2.36.0 and 3.1.0, the HMAC …nvd · 2026-07-17
highCVE-2026-49211: Symfony UX is a JavaScript ecosystem for Symfony. From 2.2.0 until 2.36.0 and 3.1.0, Symfony\U…nvd · 2026-07-17
mediumCVE-2026-49210: Symfony UX is a JavaScript ecosystem for Symfony. From 2.8.0 until 2.36.0 and 3.1.0, Symfony\U…nvd · 2026-07-17
mediumCVE-2026-49209: Symfony UX is a JavaScript ecosystem for Symfony. From 2.5.0 until 2.36.0 and 3.1.0, Symfony\U…nvd · 2026-07-17