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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-45304

34
FAUCET Score

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.

First published: Jul 14, 2026Last modified: Jul 14, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 5.4.52CPE matchmatch criteria
cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
>= 6.0.0, < 6.4.40CPE matchmatch criteria
cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
>= 7.0.0, < 7.4.12CPE matchmatch criteria
cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
>= 8.0.0, < 8.0.12CPE matchmatch criteria
cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

8.7HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
NONE
VS Integrity
NONE
VS Availability
HIGH
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.80%
Probability of exploitation in next 30 days
EPSS Percentile
53.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0080 is in the 28th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (8)

composerpatch availablevia ghsa
Product: symfony/yamlFixed in: 5.4.52
composerpatch availablevia ghsa
Product: symfony/symfonyFixed in: 5.4.52
composerpatch availablevia ghsa
Product: symfony/symfonyFixed in: 6.4.40
composerpatch availablevia ghsa
Product: symfony/symfonyFixed in: 7.4.12
composerpatch availablevia ghsa
Product: symfony/symfonyFixed in: 8.0.12
composerpatch availablevia ghsa
Product: symfony/yamlFixed in: 6.4.40
composerpatch availablevia ghsa
Product: symfony/yamlFixed in: 7.4.12
composerpatch availablevia ghsa
Product: symfony/yamlFixed in: 8.0.12

Vendor Advisories (1)

composerGHSA-4qpc-3hr4-r2p4low

Symfony's YAML Parser Vulnerable to Exponential Memory Allocation via Recursive Collection-Alias Expansion ("Billion Laughs")

May 27, 2026

References

github.com / symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a
Patch
github.com / symfony/symfony/releases/tag/v5.4.52
ProductRelease Notes
github.com / symfony/symfony/releases/tag/v6.4.40
ProductRelease Notes
github.com / symfony/symfony/releases/tag/v7.4.12
ProductRelease Notes
github.com / symfony/symfony/releases/tag/v8.0.12
ProductRelease Notes
github.com / symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4
PatchVendor Advisory