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TI-2026-33105 Aliases CVE-2026-45305GHSA-9frc-8383-795m

Symfony: YAML Parser ReDoS via Catastrophic Backtracking in Parser::cleanup() Regex

Priority MEDIUM 45CWE-1333Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-1333.

Summary

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::cleanup() used regular expressions with overlapping quantifiers for YAML directive, comment, and document marker cleanup, allowing crafted input to make parsing hang for an arbitrarily long time. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00684 52nd percentileScored 2026-11-07
Fix Fixed symfony (symfony): 5.4.52, 6.4.40, 7.4.12 +1yaml (symfony): 5.4.52, 6.4.40, 7.4.12 +1+2 more products

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
symfonysymfonybefore 5.4.52; 6.0.0-BETA1 to before 6.4.40; 7.0.0-BETA1 to before 7.4.12; 8.0.0-BETA1 to before 8.0.125.4.52, 6.4.40, 7.4.12, 8.0.12Patch availableCNA
symfonyyamlbefore 5.4.52; 6.0.0-BETA1 to before 6.4.40; 7.0.0-BETA1 to before 7.4.12; 8.0.0-BETA1 to before 8.0.125.4.52, 6.4.40, 7.4.12, 8.0.12Patch availableCNA
—symfony/yaml (Packagist)before 5.4.525.4.52Patch availableGHSA-9frc-8383-795m
—symfony/symfony (Packagist)before 5.4.525.4.52Patch availableGHSA-9frc-8383-795m
—symfony/symfony (Packagist)6.0.0 to before 6.4.406.4.40Patch availableGHSA-9frc-8383-795m
—symfony/symfony (Packagist)7.0.0 to before 7.4.127.4.12Patch availableGHSA-9frc-8383-795m
—symfony/symfony (Packagist)8.0.0 to before 8.0.128.0.12Patch availableGHSA-9frc-8383-795m
—symfony/yaml (Packagist)6.0.0 to before 6.4.406.4.40Patch availableGHSA-9frc-8383-795m
—symfony/yaml (Packagist)7.0.0 to before 7.4.127.4.12Patch availableGHSA-9frc-8383-795m
—symfony/yaml (Packagist)8.0.0 to before 8.0.128.0.12Patch availableGHSA-9frc-8383-795m
  • symfony Vendorsymfony Affected before 5.4.52; 6.0.0-BETA1 to before 6.4.40; 7.0.0-BETA1 to before 7.4.12; 8.0.0-BETA1 to before 8.0.12 Fixed in 5.4.52, 6.4.40, 7.4.12, 8.0.12 Patch available CNA
  • yaml Vendorsymfony Affected before 5.4.52; 6.0.0-BETA1 to before 6.4.40; 7.0.0-BETA1 to before 7.4.12; 8.0.0-BETA1 to before 8.0.12 Fixed in 5.4.52, 6.4.40, 7.4.12, 8.0.12 Patch available CNA
  • symfony/yaml (Packagist) Vendor— Affected before 5.4.52 Fixed in 5.4.52 Patch available GHSA-9frc-8383-795m
  • symfony/symfony (Packagist) Vendor— Affected before 5.4.52 Fixed in 5.4.52 Patch available GHSA-9frc-8383-795m
  • symfony/symfony (Packagist) Vendor— Affected 6.0.0 to before 6.4.40 Fixed in 6.4.40 Patch available GHSA-9frc-8383-795m
  • symfony/symfony (Packagist) Vendor— Affected 7.0.0 to before 7.4.12 Fixed in 7.4.12 Patch available GHSA-9frc-8383-795m
  • symfony/symfony (Packagist) Vendor— Affected 8.0.0 to before 8.0.12 Fixed in 8.0.12 Patch available GHSA-9frc-8383-795m
  • symfony/yaml (Packagist) Vendor— Affected 6.0.0 to before 6.4.40 Fixed in 6.4.40 Patch available GHSA-9frc-8383-795m
  • symfony/yaml (Packagist) Vendor— Affected 7.0.0 to before 7.4.12 Fixed in 7.4.12 Patch available GHSA-9frc-8383-795m
  • symfony/yaml (Packagist) Vendor— Affected 8.0.0 to before 8.0.12 Fixed in 8.0.12 Patch available GHSA-9frc-8383-795m

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*before 5.4.52; 6.0.0 to before 6.4.40; 7.0.0 to before 7.4.12; 8.0.0 to before 8.0.12Vulnerablesensiolabs
  • cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:* Versions before 5.4.52; 6.0.0 to before 6.4.40; 7.0.0 to before 7.4.12; 8.0.0 to before 8.0.12 Vulnerable ·sensiolabs

Remediation

  • Fix · CNA symfony (symfony) Fixed in 5.4.52, 6.4.40, 7.4.12, 8.0.12
  • Fix · CNA yaml (symfony) Fixed in 5.4.52, 6.4.40, 7.4.12, 8.0.12
  • Fix · GHSA-9frc-8383-795m symfony/yaml (Packagist) Fixed in 5.4.52 Advisory →
  • Fix · GHSA-9frc-8383-795m symfony/symfony (Packagist) Fixed in 5.4.52 Advisory →
  • Fix · GHSA-9frc-8383-795m symfony/symfony (Packagist) Fixed in 6.4.40 Advisory →
  • Fix · GHSA-9frc-8383-795m symfony/symfony (Packagist) Fixed in 7.4.12 Advisory →
  • Fix · GHSA-9frc-8383-795m symfony/symfony (Packagist) Fixed in 8.0.12 Advisory →
  • Fix · GHSA-9frc-8383-795m symfony/yaml (Packagist) Fixed in 6.4.40 Advisory →
  • Fix · GHSA-9frc-8383-795m symfony/yaml (Packagist) Fixed in 7.4.12 Advisory →
  • Fix · GHSA-9frc-8383-795m symfony/yaml (Packagist) Fixed in 8.0.12 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-45305
  2. 2026-10-03 Alias added: GHSA-9frc-8383-795m

References

Patch 2

Other 8

  • TI-2024-33775 Ability to change environment from query in symfony/runtime CVSS 3.1HIGH 7.3
  • TI-2026-34283 Twig: The `spaceless` filter implicitly marks its output as safe CVSS 4.0MEDIUM 5.1
  • TI-2022-07667 Code injection in Twig CVSS 3.1CRITICAL 9.8
  • TI-2018-10028 Twig before 2.4.4 allows Server-Side Template Injection (SSTI) via the search search_key… CVSS 3.0CRITICAL 9.8
  • TI-2026-35851 Incorrect authorization in symfony CVSS 4.0HIGH 8.7
  • TI-2026-35264 Improper input validation in symfony CVSS 4.0HIGH 8.3
See all 94 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences