Skip to content
OpenAdvisories

Weakness (CWE)

CWE-626: Null Byte Interaction Error (Poison Null Byte)

Variant Draft

The product does not properly handle null bytes or NUL characters when passing data between different representations or components.

More detail

A null byte (NUL character) can have different meanings across representations or languages. For example, it is a string terminator in standard C libraries, but Perl and PHP strings do not treat it as a terminator. When two representations are crossed - such as when Perl or PHP invokes underlying C functionality - this can produce an interaction error with unexpected results. Similar issues have been reported for ASP. Other interpreters written in C might also be affected.

The poison null byte is frequently useful in path traversal attacks by terminating hard-coded extensions that are added to a filename. It can play a role in regular expression processing in PHP.

How to prevent it (1 mitigation)
  1. Implementation

    Remove null bytes from all incoming strings.

Source: MITRE CWE-626

2 results · Clear filters · Feed

  • High 7.5

    Netty: DNS Codec Input Validation Bypass in Netty (Encoder + Decoder)

    Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's DNS codec does not enforce RFC 1035 domain name constraints during either encoding or decoding. This creates a bidirectional attack surface:…

  • High 7.1

    Gnutls: gnutls: authentication bypass via nul character in username

    A flaw was found in gnutls. Servers configured with RSA-PSK (Rivest–Shamir–Adleman – Pre-Shared Key) wrongfully matched usernames containing a NUL character with truncated usernames. A remote attacker could exploit this by sending a specially crafted username…