CVE-2026-77634
CakePHP mail header injection via Message::setHeaders/addHeaders (CRLF not removed).
Is CVE-2026-77634 being exploited?
Not confirmed. CVE-2026-77634 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.31% probability of exploitation in the next 30 days.
How severe is CVE-2026-77634?
CVE-2026-77634 is rated High. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-77634?
Yes. A fix has been recorded for CVE-2026-77634. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-77634 affect?
CVE-2026-77634 affects CakePHP Message::setHeaders(), CakePHP Message::addHeaders(), CakePHP < 4.5.12, CakePHP < 4.6.5, and 3 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-77634?
Upgrade to 4.5.12 / 4.6.5 / 5.1.8 / 5.2.14 / 5.3.7 immediately
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attackers can inject CRLF into custom mail headers to spoof emails, add BCC/CC, perform mail-splitting/phishing and abuse SMTP delivery.
Patch when possible
- affected>= 4.5.0 and < 4.5.12
- affected>= 4.6.0 and < 4.6.5
- affected>= 5.0.0 and < 5.1.9
- affected>= 5.2.0 and < 5.2.14
- affected>= 5.3.0 and < 5.3.7
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.