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Not in CISA KEV
HIGH severity

CVE-2013-4751 — validator

HIGH

CVE-2013-4751 is a high-severity (CVSS 8.1) Improper Input Validation vulnerability in symfony/validator. A fix is available for symfony/validator — see the affected versions and patch details below.

Symfony collectionCascaded and collectionCascadedDeeply fields security bypass

Published
Updated
Affected
8 pkgs
Patched
8 / 8
Exploits
None indexed
Exploitation data as of Oct 31, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs73th percentile — riskier than 73% of all scored CVEsHighest risk
0.07%0.69%1.32%1.94%0.6%1.4%May 26Sep 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

8 pkgs affected
🐘symfony/validator🐘symfony/validator🐘symfony/validator🐘symfony/validator🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony🐘symfony/symfony

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

When using the Validator component, if Symfony\\Component\\Validator\\Mapping\\Cache\\ApcCache is enabled (or any other cache implementing Symfony\\Component\\Validator\\Mapping\\Cache\\CacheInterface), some information is lost during serialization (the collectionCascaded and the collectionCascadedDeeply fields).

As a consequence, arrays or traversable objects stored in fields using the @Valid constraint are not traversed by the validator as soon as the validator configuration is loaded from the cache.

Affected Packages

8 total 8 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistsymfony/validator≥ 2.0.0&&< 2.0.242.0.24composer require symfony/validator:^2.0.24
🐘Packagistsymfony/validator≥ 2.1.0&&< 2.1.122.1.12composer require symfony/validator:^2.1.12
🐘Packagistsymfony/validator≥ 2.2.0&&< 2.2.52.2.5composer require symfony/validator:^2.2.5
🐘Packagistsymfony/validator≥ 2.3.0&&< 2.3.32.3.3composer require symfony/validator:^2.3.3
🐘Packagistsymfony/symfony≥ 2.0.0&&< 2.0.242.0.24composer require symfony/symfony:^2.0.24
🐘Packagistsymfony/symfony≥ 2.1.0&&< 2.1.122.1.12composer require symfony/symfony:^2.1.12

Affected Products

3 products · 7 configurations
OS
fedorafedoraproject
2 versions
1819
OS
enterprise linuxredhat
1 version
6.0
Application
symfonysensiolabs
≥ 2.3.0 && < 2.3.3
range

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/validator, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update symfony/validator to 2.0.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2013-4751 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

When using the Validator component, if `Symfony\\Component\\Validator\\Mapping\\Cache\\ApcCache` is enabled (or any other cache implementing `Symfony\\Component\\Validator\\Mapping\\Cache\\CacheInterface`), some information is lost during serialization (the `collectionCascaded` and the `collectionCascadedDeeply` fields). As a consequence, arrays or traversable objects stored in fields using the `@Valid` constraint are not traversed by the validator as soon as the validator configuration is loaded from the cache.
O3 Security · Impact-Aware SCA

Is CVE-2013-4751 in your dependencies?

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CVE-2013-4751: validator — Fixed in 2.0.24