freestate freestate - 1 year ago 312
PHP Question

Error with PHP mail(): Multiple or malformed newlines found in additional_header

Suddenly have started receiving the above error without any changes having been made to the script.

Host is 1and1 (I know...)

The script still works fine on a different server, and so my suspicion is that there must have been some server config change that has lead to this, although the hosts plead ignorance.

There's no information on the above error at all in Google that I can find - does anybody have any ideas? Server is running Apache if that helps.

Answer Source

Had just the similar problem.
It came out of the blue. No PHP Code was changed.

What was changed: PHP was upgraded 5.5.25-1 to 5.5.26.

A security risk in PHP mail() function has been fixed and extra newlines in additional_headers are allowed no more. Because extra newlines mean: now starts the email message (and we surely don't want somebody to inject some newlines through headers followed by an evil message).

What previously have worked fine, e.g. just having extra newlines after headers or even passing the whole message to additional_headers, will function no more.


  • Sanitize your headers. No multiple newlines in additional_headers argument. These count as "multiple or malformed newlines": \r\r, \r\0, \r\n\r\n, \n\n, \n\0.
  • Use additional_headers for headers only. Email message (multipart or not, with ir without attachments, etc) belongs in message argument, not in headers.

PHP Security Bug report:
C Code diff how its fixed:;a=blobdiff;f=ext/standard/mail.c;h=448013a472a3466245e64b1cb37a9d1b0f7c007e;hp=1ebc8fecb7ef4c266a341cdc701f0686d6482242;hb=9d168b863e007c4e15ebe4d2eecabdf8b0582e30;hpb=eee8b6c33fc968ef8c496db8fb54e8c9d9d5a8f9

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