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Is symfony/yaml vulnerable?

6 known security advisories for symfony/yaml. The latest was reported on 2026-08-30 and is fixed in 3.0.0, 4.0.0, 5.0.0, 5.1.0, 5.2.0, 5.3.0, 5.4.0, 5.4.54, 6.1.0, 6.2.0, 6.3.0, 6.4.0, 6.4.45, 7.1.0, 7.2.0, 7.3.0, 7.4.0, 7.4.18, 8.1.0 and 8.1.6. The newest release, 8.1.10, is not affected by any of them.

3 high 3 low

Known advisories
6
Newest release
8.1.10
Released
2026-10-18
Affecting newest release
0
Last synced
2026-11-03

Loads and dumps YAML files · packagist.org/packages/symfony/yaml

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Run composer show symfony/yaml in your project to see the installed version, then enter it here.

Security advisories for symfony/yaml

Newest first. “Affected” is the Composer version constraint from the advisory; “fixed in” is each version the advisory names as the first safe one on its release line.

ReportedAdvisorySeverityAffectedFixed in
2026-08-30 CVE-2026-109413: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process CVE-2026-109413 · GitHub, FriendsOfPHP/security-advisories high >=2.0.0,<3.0.0 | >=3.0.0,<4.0.0 | >=4.0.0,<5.0.0 | >=5.0.0,<5.1.0 | >=5.1.0,<5.2.0 | >=5.2.0,<5.3.0 | >=5.3.0,<5.4.0 | >=5.4.0,<5.4.54 | >=6.0.0,<6.1.0 | >=6.1.0,<6.2.0 | >=6.2.0,<6.3.0 | >=6.3.0,<6.4.0 | >=6.4.0,<6.4.45 | >=7.0.0,<7.1.0 | >=7.1.0,<7.2.0 | >=7.2.0,<7.3.0 | >=7.3.0,<7.4.0 | >=7.4.0,<7.4.18 | >=8.0.0,<8.1.0 | >=8.1.0,<8.1.6 3.0.0, 4.0.0, 5.0.0, 5.1.0, 5.2.0, 5.3.0, 5.4.0, 5.4.54, 6.1.0, 6.2.0, 6.3.0, 6.4.0, 6.4.45, 7.1.0, 7.2.0, 7.3.0, 7.4.0, 7.4.18, 8.1.0, 8.1.6
2026-05-20 CVE-2026-45304: YAML Parser Exponential Memory Allocation via Recursive Collection-Alias Expansion ("Billion Laughs") CVE-2026-45304 · GitHub, FriendsOfPHP/security-advisories low >=2.0.0,<3.0.0 | >=3.0.0,<4.0.0 | >=4.0.0,<5.0.0 | >=5.0.0,<5.1.0 | >=5.1.0,<5.2.0 | >=5.2.0,<5.3.0 | >=5.3.0,<5.4.0 | >=5.4.0,<5.4.52 | >=6.0.0,<6.1.0 | >=6.1.0,<6.2.0 | >=6.2.0,<6.3.0 | >=6.3.0,<6.4.0 | >=6.4.0,<6.4.40 | >=7.0.0,<7.1.0 | >=7.1.0,<7.2.0 | >=7.2.0,<7.3.0 | >=7.3.0,<7.4.0 | >=7.4.0,<7.4.12 | >=8.0.0,<8.0.12 3.0.0, 4.0.0, 5.0.0, 5.1.0, 5.2.0, 5.3.0, 5.4.0, 5.4.52, 6.1.0, 6.2.0, 6.3.0, 6.4.0, 6.4.40, 7.1.0, 7.2.0, 7.3.0, 7.4.0, 7.4.12, 8.0.12
2026-05-20 CVE-2026-45305: YAML Parser ReDoS via Catastrophic Backtracking in Parser::cleanup() Regex CVE-2026-45305 · GitHub, FriendsOfPHP/security-advisories low >=2.0.0,<3.0.0 | >=3.0.0,<4.0.0 | >=4.0.0,<5.0.0 | >=5.0.0,<5.1.0 | >=5.1.0,<5.2.0 | >=5.2.0,<5.3.0 | >=5.3.0,<5.4.0 | >=5.4.0,<5.4.52 | >=6.0.0,<6.1.0 | >=6.1.0,<6.2.0 | >=6.2.0,<6.3.0 | >=6.3.0,<6.4.0 | >=6.4.0,<6.4.40 | >=7.0.0,<7.1.0 | >=7.1.0,<7.2.0 | >=7.2.0,<7.3.0 | >=7.3.0,<7.4.0 | >=7.4.0,<7.4.12 | >=8.0.0,<8.0.12 3.0.0, 4.0.0, 5.0.0, 5.1.0, 5.2.0, 5.3.0, 5.4.0, 5.4.52, 6.1.0, 6.2.0, 6.3.0, 6.4.0, 6.4.40, 7.1.0, 7.2.0, 7.3.0, 7.4.0, 7.4.12, 8.0.12
2026-05-20 CVE-2026-45133: YAML Parser Stack Exhaustion via Unbounded Recursion in Nested Blocks, Sequences, and Mappings CVE-2026-45133 · GitHub, FriendsOfPHP/security-advisories low >=2.0.0,<3.0.0 | >=3.0.0,<4.0.0 | >=4.0.0,<5.0.0 | >=5.0.0,<5.1.0 | >=5.1.0,<5.2.0 | >=5.2.0,<5.3.0 | >=5.3.0,<5.4.0 | >=5.4.0,<5.4.52 | >=6.0.0,<6.1.0 | >=6.1.0,<6.2.0 | >=6.2.0,<6.3.0 | >=6.3.0,<6.4.0 | >=6.4.0,<6.4.40 | >=7.0.0,<7.1.0 | >=7.1.0,<7.2.0 | >=7.2.0,<7.3.0 | >=7.3.0,<7.4.0 | >=7.4.0,<7.4.12 | >=8.0.0,<8.0.12 3.0.0, 4.0.0, 5.0.0, 5.1.0, 5.2.0, 5.3.0, 5.4.0, 5.4.52, 6.1.0, 6.2.0, 6.3.0, 6.4.0, 6.4.40, 7.1.0, 7.2.0, 7.3.0, 7.4.0, 7.4.12, 8.0.12
2013-01-15 Ability to enable/disable object support in YAML parsing and dumping CVE-2013-1397 · GitHub, FriendsOfPHP/security-advisories high >=2.0.0,<2.0.22 | >=2.1.0,<2.1.7 2.0.22, 2.1.7
2013-01-15 Ability to enable/disable PHP parsing in Yaml::parse() CVE-2013-1348 · GitHub, FriendsOfPHP/security-advisories high >=2.0.0,<2.0.22 2.0.22

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Questions about symfony/yaml

Does symfony/yaml have known vulnerabilities?

Yes. Packagist lists 6 security advisories for symfony/yaml (3 high, 3 low severity). The most recent, reported 2026-08-30, is "CVE-2026-109413: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process". The newest release, 8.1.10, is outside every affected range.

Which version of symfony/yaml should I run?

The newest stable release is 8.1.10 (published 2026-10-18). The most recent advisory is fixed in 3.0.0, 4.0.0, 5.0.0, 5.1.0, 5.2.0, 5.3.0, 5.4.0, 5.4.54, 6.1.0, 6.2.0, 6.3.0, 6.4.0, 6.4.45, 7.1.0, 7.2.0, 7.3.0, 7.4.0, 7.4.18, 8.1.0 and 8.1.6, so stay on or above the fixed version for your major version. Run composer update symfony/yaml, then composer audit to confirm nothing else is flagged.

How do I check if my symfony/yaml version is affected?

Run composer show symfony/yaml in your project to see the installed version, then enter it in the version check on this page. You can also run composer audit, which reads the same Packagist advisory data for every package in your composer.lock.

Where this data comes from

Advisories come from the Packagist security advisories API, which collects the GitHub Advisory Database and the FriendsOfPHP security advisories. composer audit reads the same data. Releases come from packagist.org. Last synced 2026-11-03; we re-check daily. Each advisory links to its source. Spot an error? Tell us.

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