The MITRE CVE dictionary describes this issue as:
drivers/net/r8169.c in the r8169 driver in the Linux kernel 22.214.171.124 and earlier does not properly check the size of an Ethernet frame that exceeds the MTU, which allows remote attackers to (1) cause a denial of service (temporary network outage) via a packet with a crafted size, in conjunction with certain packets containing A characters and certain packets containing E characters; or (2) cause a denial of service (system crash) via a packet with a crafted size, in conjunction with certain packets containing '\\0' characters, related to the value of the status register and erroneous behavior associated with the RxMaxSize register. NOTE: this vulnerability exists because of an incorrect fix for CVE-2009-1389.
Find out more about CVE-2009-4537 from the
MITRE CVE dictionary dictionary and