CVE-2026-77634: CakePHP SmtpTransport Vulnerable To CRLF Header Vulnerability
HIGHCVE-2026-77634 is a HIGH smtptransport vulnerable to crlf header vulnerability (CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')) affecting CakePHP libraries in the Packagist ecosystem. The issue involves smtptransport vulnerable to crlf header injection. Remediation is available by upgrading affected packages to version 4.5.12, 4.6.5, 5.1.9, 5.2.14, 5.3.7.
CVE-2026-77634 at a Glance
How to Fix CVE-2026-77634
To remediate this vulnerability, upgrade all affected CakePHP 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 cakephp/cakephp to 4.5.12Upgrade cakephp/cakephp to 4.6.5Upgrade cakephp/cakephp to 5.1.9Upgrade cakephp/cakephp to 5.2.14Upgrade cakephp/cakephp to 5.3.7Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for cakephp/cakephpHow to Check if You Are Affected
To determine whether your application is affected by CVE-2026-77634, inspect your project dependencies for CakePHP:
inspect dependencies for cakephp/cakephpAnalyze the terminal output to locate any version of CakePHP in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.5.12), 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-93: Improper Neutralization of CRLF Sequences ('CRLF Injection'), where the product uses crlf (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes crlf sequences from inputs. In CakePHP, 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-2026-77634 Affected CakePHP Versions
5 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
cakephp/cakephp
|
Packagist |
≥ 4.5.0
< 4.5.12
|
4.5.12
|
|
cakephp/cakephp
|
Packagist |
≥ 4.6.0
< 4.6.5
|
4.6.5
|
|
cakephp/cakephp
|
Packagist |
≥ 5.0.0
< 5.1.9
|
5.1.9
|
|
cakephp/cakephp
|
Packagist |
≥ 5.2.0
< 5.2.14
|
5.2.14
|
|
cakephp/cakephp
|
Packagist |
≥ 5.3.0
< 5.3.7
|
5.3.7
|
References
Frequently Asked Questions
What is CVE-2026-77634?
Which CakePHP versions are affected?
What version fixes CVE-2026-77634?
Is cakephp/cakephp affected?
What CWE is associated with CVE-2026-77634?
How can I check Packagist dependencies for CVE-2026-77634?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-2qh5-382h-3jpc",
"modified" : "2026-09-08T20:56:26Z",
"published" : "2026-09-08T20:56:26Z",
"aliases" : [ "CVE-2026-77634" ],
"summary" : "CakePHP: SmtpTransport vulnerable to CRLF header injection",
"details" : "### Impact\n\nCustom mail headers added with `Message::setHeaders()` or `addHeaders()` do not have CRLF replaced allowing header injection if user controlled data is added to message headers without stripping CRLF bytes.\n\n### Patches\n5.3.7, 5.2.14, 5.1.9, 4.6.5, 4.5.12 contain fixes for this issue.\n\n### Workarounds\nYou can strip CRLF bytes from email header values before setting header values.",
"severity" : [ {
"type" : "CVSS_V4",
"score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Packagist",
"name" : "cakephp/cakephp"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.5.0"
}, {
"fixed" : "4.5.12"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "cakephp/cakephp"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.6.0"
}, {
"fixed" : "4.6.5"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "cakephp/cakephp"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "5.0.0"
}, {
"fixed" : "5.1.9"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "< 5.1.8"
}
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "cakephp/cakephp"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "5.2.0"
}, {
"fixed" : "5.2.14"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "cakephp/cakephp"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "5.3.0"
}, {
"fixed" : "5.3.7"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/cakephp/cakephp/security/advisories/GHSA-2qh5-382h-3jpc"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-77634"
}, {
"type" : "WEB",
"url" : "https://github.com/cakephp/cakephp/commit/08188962bcd99a95da1e49f62e786f2d688f1e41"
}, {
"type" : "WEB",
"url" : "https://github.com/cakephp/cakephp/commit/2afe42b02d8ddc5d442bca5e8bb61910a727646e"
}, {
"type" : "WEB",
"url" : "https://github.com/cakephp/cakephp/commit/3e09dae6cbdc983754fa3a8e6aae74da102a3ea1"
}, {
"type" : "WEB",
"url" : "https://github.com/cakephp/cakephp/commit/b67b622457362b075bb37e625a82af73a0b3c9c3"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/cakephp/cakephp"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-93" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-09-08T20:56:26Z",
"nvd_published_at" : "2026-08-24T21:17:48Z"
}
}