CVE-2021-29454: Smarty/smarty Sandbox Escape By Math Function Vulnerability
HIGHCVE-2021-29454 is a HIGH (CVSS 8.1) sandbox escape by math function vulnerability (CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')) affecting Smarty/smarty libraries in the Packagist ecosystem. The issue involves sandbox escape by math function in smarty. Remediation is available by upgrading affected packages to version 3.1.42, 4.0.2.
CVE-2021-29454 at a Glance
Security Impact
CVSS: 8.1
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N).
How to Fix CVE-2021-29454
To remediate this vulnerability, upgrade all affected Smarty/smarty dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade smarty/smarty to 3.1.42Upgrade smarty/smarty to 4.0.2Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for smarty/smartyHow to Check if You Are Affected
To determine whether your application is affected by CVE-2021-29454, inspect your project dependencies for Smarty/smarty:
inspect dependencies for smarty/smartyAnalyze the terminal output to locate any version of Smarty/smarty in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.1.42), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection'), where the product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. In Smarty/smarty, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2021-29454 Affected Smarty/smarty Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
smarty/smarty
|
Packagist |
< 3.1.42
|
3.1.42
|
|
smarty/smarty
|
Packagist |
≥ 4.0.0
< 4.0.2
|
4.0.2
|
References
Frequently Asked Questions
What is CVE-2021-29454?
Which Smarty/smarty versions are affected?
What version fixes CVE-2021-29454?
Is smarty/smarty affected?
What is the CVSS score of CVE-2021-29454?
What CWE is associated with CVE-2021-29454?
How can I check Packagist dependencies for CVE-2021-29454?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-29gp-2c3m-3j6m",
"modified" : "2022-01-20T15:34:11Z",
"published" : "2022-01-12T22:43:00Z",
"aliases" : [ "CVE-2021-29454" ],
"summary" : "Sandbox Escape by math function in smarty",
"details" : "### Impact\nTemplate authors could run arbitrary PHP code by crafting a malicious math string.\nIf a math string is passed through as user provided data to the math function, external users could run arbitrary PHP code by crafting a malicious math string.\n\n### Patches\nPlease upgrade to 4.0.2 or 3.1.42 or higher.\n\n### References\nSee [documentation on Math function](https://www.smarty.net/docs/en/language.function.math.tpl).\n\n### For more information\nIf you have any questions or comments about this advisory please open an issue in [the Smarty repo](https://github.com/smarty-php/smarty)\n",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Packagist",
"name" : "smarty/smarty"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "3.1.42"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "smarty/smarty"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.0.0"
}, {
"fixed" : "4.0.2"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/smarty-php/smarty/security/advisories/GHSA-29gp-2c3m-3j6m"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-29454"
}, {
"type" : "WEB",
"url" : "https://github.com/smarty-php/smarty/commit/215d81a9fa3cd63d82fb3ab56ecaf97cf1e7db71"
}, {
"type" : "WEB",
"url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/smarty/smarty/CVE-2021-29454.yaml"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/smarty-php/smarty"
}, {
"type" : "WEB",
"url" : "https://github.com/smarty-php/smarty/releases/tag/v3.1.42"
}, {
"type" : "WEB",
"url" : "https://github.com/smarty-php/smarty/releases/tag/v4.0.2"
}, {
"type" : "WEB",
"url" : "https://lists.debian.org/debian-lts-announce/2022/05/msg00005.html"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BRAJVDRGCIY5UZ2PQHKDTT7RMKG6WJQQ"
}, {
"type" : "WEB",
"url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/L777JIBIWJV34HS7LXPIDWASG7TT4LNI"
}, {
"type" : "WEB",
"url" : "https://packagist.org/packages/smarty/smarty"
}, {
"type" : "WEB",
"url" : "https://security.gentoo.org/glsa/202209-09"
}, {
"type" : "WEB",
"url" : "https://www.debian.org/security/2022/dsa-5151"
}, {
"type" : "WEB",
"url" : "https://www.smarty.net/docs/en/language.function.math.tpl"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-74" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2022-01-10T22:08:56Z",
"nvd_published_at" : "2022-01-10T20:15:00Z"
}
}