CVE-2026-45133
Symfony: [Yaml] Harden the parser when handling untrusted input
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, when the parser is exposed to attacker-controlled input, deeply nested mappings or sequences cause both the block-level (Parser::parseBlock()) and inline (Inline::parseSequence() / Inline::parseMapping()) parsers to recurse without a depth limit. A crafted document exhausts the PHP stack and crashes the worker. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
INFO
Published Date :
July 14, 2026, 7:17 p.m.
Last Modified :
July 15, 2026, 2:54 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Symfony to version 5.4.52 or later.
- Update Symfony to version 6.4.40 or later.
- Update Symfony to version 7.4.12 or later.
- Update Symfony to version 8.0.12 or later.
Public PoC/Exploit Available at Github
CVE-2026-45133 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-45133.
| URL | Resource |
|---|---|
| https://github.com/symfony/symfony/releases/tag/v5.4.52 | Product Release Notes |
| https://github.com/symfony/symfony/releases/tag/v6.4.40 | Product Release Notes |
| https://github.com/symfony/symfony/releases/tag/v7.4.12 | Product Release Notes |
| https://github.com/symfony/symfony/releases/tag/v8.0.12 | Product Release Notes |
| https://github.com/symfony/symfony/security/advisories/GHSA-c2p3-7m5p-cv8x | Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-45133 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-45133
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Shared reusable GitHub Actions workflow: normalizes SAST/DAST/SCA scanner findings and generates a Gemini-powered, CWE-aware, risk-prioritized PR comment
Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-45133 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-45133 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 15, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:* versions from (including) 7.0.0 up to (excluding) 7.4.12 *cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:* versions from (including) 8.0.0 up to (excluding) 8.0.12 *cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:* versions up to (excluding) 5.4.52 *cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:* versions from (including) 6.0.0 up to (excluding) 6.4.40 Added Reference Type GitHub, Inc.: https://github.com/symfony/symfony/releases/tag/v5.4.52 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/symfony/symfony/releases/tag/v6.4.40 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/symfony/symfony/releases/tag/v7.4.12 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/symfony/symfony/releases/tag/v8.0.12 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/symfony/symfony/security/advisories/GHSA-c2p3-7m5p-cv8x Types: Patch, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 15, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-45133', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-15T13:25:18.252487Z'} -
New CVE Received by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'symfony', 'product': 'symfony', 'versions': [{'status': 'affected', 'version': '< 5.4.52'}, {'status': 'affected', 'version': '>= 6.0.0-BETA1, < 6.4.40'}, {'status': 'affected', 'version': '>= 7.0.0-BETA1, < 7.4.12'}, {'status': 'affected', 'version': '>= 8.0.0-BETA1, < 8.0.12'}]}] Added 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, when the parser is exposed to attacker-controlled input, deeply nested mappings or sequences cause both the block-level (Parser::parseBlock()) and inline (Inline::parseSequence() / Inline::parseMapping()) parsers to recurse without a depth limit. A crafted document exhausts the PHP stack and crashes the worker. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12. Added CVSS V4.0 AV:N/AC:L/AT:P/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 Added CWE CWE-674 Added CWE CWE-776 Added CWE CWE-1333 Added Reference https://github.com/symfony/symfony/releases/tag/v5.4.52 Added Reference https://github.com/symfony/symfony/releases/tag/v6.4.40 Added Reference https://github.com/symfony/symfony/releases/tag/v7.4.12 Added Reference https://github.com/symfony/symfony/releases/tag/v8.0.12 Added Reference https://github.com/symfony/symfony/security/advisories/GHSA-c2p3-7m5p-cv8x