Severity: moderate
Affected versions:
- Apache Camel (org.apache.camel:camel-mail) 4.0.0 before 4.14.8
- Apache Camel (org.apache.camel:camel-mail) 4.15.0 before 4.18.3
- Apache Camel (org.apache.camel:camel-mail) 4.19.0 before r
Description:
Improper Input Validation, Exposure of Sensitive Information to an Unauthorized
Actor vulnerability in Apache Camel Mail Component.
The camel-mail producer (MailProducer.getSender) scanned the outgoing Exchange
for message headers in the mail.smtp. / mail.smtps. namespace and, when any
were present, built a per-message JavaMail sender with those values applied as
JavaMail session properties, overriding the endpoint configuration. This
namespace is Camel-internal - only MailProducer interprets it - and was not
blocked by any HeaderFilterStrategy, so the values could originate from any
inbound protocol (for example platform-http query parameters or request
headers, or JMS / Kafka messages from untrusted producers) that feeds a route
ending in an smtp / smtps producer without an intervening removeHeaders. The
maximal impact is version-dependent: on releases before 4.19.0, setting
mail.smtp.host redirects the SMTP connection to a server under the attacker's
control, and because the producer then authenticates with the endpoint's
configured username and password those credentials are transmitted to the
attacker; on 4.19.0 and later the producer connects to the endpoint's
configured host explicitly, so the reachable impact is limited to weakening
transport security (for example mail.smtp.ssl.trust, mail.smtp.starttls.enable
or mail.smtp.socks.host) and interception of the outgoing message rather than
host redirect. Exploitation requires a route that channels untrusted input into
the mail producer without stripping the namespace.
This issue affects Apache Camel: from 4.0.0 before 4.14.8, from 4.15.0 before
4.18.3, from 4.19.0 before 4.21.0.
Users are recommended to upgrade to version 4.21.0, which fixes the issue. If
users are on the 4.14.x LTS releases stream, then they are suggested to upgrade
to 4.14.8. If users are on the 4.18.x releases stream, then they are suggested
to upgrade to 4.18.3. After upgrading, the per-message override is disabled by
default; enable it only on trusted endpoints with
useJavaMailSessionPropertiesFromHeaders=true. For deployments that cannot
upgrade immediately, strip the namespace before the mail producer with
removeHeaders('mail.smtp.*') and removeHeaders('mail.smtps.*') between any
untrusted ingress and the smtp / smtps producer. Even with the opt-in enabled,
route authors should still strip the namespace on any path that carries
untrusted input.
Credit:
Yu Bao from PayPal (finder)
References:
https://camel.apache.org/security/CVE-2026-46584.html
https://camel.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-46584
