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The ICMP path MTU (PMTU) discovery feature in various UNIX systems allows remote attackers to cause a denial of service by spoofing "ICMP Fragmentation needed but Don't Fragment (DF) set" packets between two target hosts, which could cause one host to lower its MTU when transmitting to the other host.
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Date Entry Created
20010404 Disclaimer: The entry creation date may reflect when the CVE-ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Modified (20131008)
Votes (Legacy)
ACCEPT(2) Frech, Meunier
NOOP(4) Christey, Cole, Wall, Ziese
Comments (Legacy)
 Christey> (prompted from Pascal Meunier) should this be treated
   as a general design issue with ICMP?  Or is it a specific
   implementation flaw that only affects Reliant?
 Meunier> It seems obvious that if one sets the MTU to just one byte
   above the size of a IP header (let's say 21 bytes), data transmission
   is not going to go anywhere fast, as the overhead will be 20 times the
   payload...  As I said for another candidate, ICMP messages should not
   be acted upon without access control.  I'm not sure that references to
   UNIX should be kept.  It seems that this should work with any OS.  It
   would be nasty if some OSes accepted an MTU of 20, as you could not
   transmit any IP data.

Proposed (Legacy)
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