Two large messages sent at the same time to Symantec Messaging Gateway (SMG) to different recipients could experience content mixing between the two messages under certain exceptional circumstances, including delivery to an incorrect set of recipients.
This issue is caused by rare collision of temporary filenames due to heavy load and backed up message processing queues.
Conditions: Two messages enter a specific part of the filtering engine at the same time. Both messages are over 512KB in size. In addition, processing of the messages is delayed at that time. This is generally due to an appliance under heavy processing load.
Outcome: There is a narrow possibility of corruption in the re-assembly of one of the messages, such that parts of the two messages are combined. This leads to the appearance that the first message was mis-delivered to the recipients of the second message, however, at least one of the message attachments would likely be unreadable. Most email clients would not be capable of detecting the corruption, in which case the corrupted message would be delivered.
This issue has been addressed with the SMG 9.5.4 release. It is recommended to keep up to date with the most current software build to access the latest bug fixes and security updates.
Messages involved are larger than 512KB.
The issue can occur in versions prior to SMG 9.5.4. There is evidence to suggest underlying product changes in SMG 9.5.2 allowed the issue to be encountered more frequently.
Imported Document ID: TECH183454
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