Improper validation of the integrity check in the Crypto PGP component of Apache Camel allows an attacker to send a message that uses the legacy OpenPGP symmetric data packet, which contains no modification‑detection code. Because the unmarshal() routine only performs the integrity verification for integrity‑protected packets and skips the check for legacy packets, a message can be altered in transit without detection. This flaw permits an attacker to tamper with the decrypted payload, potentially changing business‑critical data or triggering incorrect downstream actions. The weakness is a failure to enforce integrity protection on messages that are accepted for decryption (CWE‑354).

Apache Camel versions from 4.0.0 up to but excluding 4.18.5, and from 4.19.0 up to but excluding 4.22.1, including the 4.18.x and 4.22.x long‑term support streams, are vulnerable. The issue is tied to the Crypto PGP component responsible for handling PGP messages within Camel routes.

The vulnerability has a CVSS base score of 5.9, reflecting moderate severity. No EPSS value is available, and the flaw is not listed in the CISA KEV catalog, indicating no confirmed widespread exploitation yet. The attack requires the ability to inject or rewrite a PGP message sent to a Camel route that employs the Crypto PGP component. By sending a message that deliberately omits the integrity‑protected packet, an attacker can bypass the integrity check, modify the payload, and have the application process the tampered data. The lack of a mandatory integrity verification on decryption means the attacker can succeed without needing to break cryptographic primitives. If successful, the attacker could compromise data authenticity and potentially disrupt downstream components.