It was discovered that the Invariance Weakness of the RC4 stream cipher could be used to recover plaintext from a TLS connection, when RC4 encryption is used.

"The Invariance Weakness is an L-shape key pattern in RC4 keys, which once it exists in an RC4 key, preserves part of the state permutation intact throughout the initialization process. This intact part includes the least significant bits of the permutation, when processed by the PRGA algorithm, determines the least significant bits of the allegedly pseudo-random output stream along a long prefix of the stream."

This can lead to significant leakage of plaintext bytes from the ciphertext.

External Reference:

http://www.imperva.com/docs/HIIAttackingSSLwhenusingRC4.pdf

Memory leak in Huawei S5300EI, S5300SI, S5310HI, and S6300EI Campus series switches with software V200R003C00 before V200R003SPH011 and V200R005C00 before V200R005SPH008; S2350EI and S5300LI Campus series switches with software V200R003C00 before V200R003SPH011, V200R005C00 before V200R005SPH008, and V200R006C00 before V200R006SPH002; S9300, S7700, and S9700 Campus series switches with software V200R003C00 before V200R003SPH011, V200R005C00 before V200R005SPH009, and V200R006C00 before V200R006SPH003; S5720HI and S5720EI Campus series switches with software V200R006C00 before V200R006SPH002; and S2300 and S3300 Campus series switches with software V100R006C05 before V100R006SPH022 allows remote authenticated users to cause a denial of service (memory consumption and device restart) by logging in and out of the (1) HTTPS or (2) SFTP server, related to SSL session information.