CVE-2026-53151rxrpc: Fix the ACK parser to extract the SACK table for parsing

Official description

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix the ACK parser to extract the SACK table for parsing Fix modification of the received skbuff in rxrpc_input_soft_acks() and a potential incorrect access of the buffer in a fragmented UDP packet (the packet would probably have to be deliberately pre-generated as fragmented) when AF_RXRPC tries to extract the contents of the SACK table by copying out the contents of the SACK table into a buffer before attempting to parse AF_RXRPC assumes that it can just call skb_condense() and then validly access the SACK table from skb->data and that it will be a flat buffer - but skb_condense() can silently fail to do anything under some circumstances. Note that whilst rxrpc_input_soft_acks() should be able to parse extended ACKs, the rest of AF_RXRPC doesn't currently support that. Further, there's then no need to call skb_condense() in rxrpc_input_ack(), so don't.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/5d1ae4e17a3ecd8561cdb4f4f70152f41039c4e1
• https://git.kernel.org/stable/c/775c5e89272a2615b72bb84f611ba66fa3b7493e
• https://git.kernel.org/stable/c/566c4c1244de50fbff1f89ff93c9d7b0fc256db4
• https://git.kernel.org/stable/c/224298450be5c04d2a6ea1c2a94669d7ebf65d00
• https://git.kernel.org/stable/c/333b6d5bb9f87827ac2639c737bf9613dbae7253