Medium [CVE-2026-72464] Repost Receive buffers for malformed replies
This medium-severity Red Hat Linux advisory covers CVE-2026-72464 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 8.
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Summary
In the Linux kernel, the following vulnerability has been resolved: xprtrdma: Repost Receive buffers for malformed replies rpcrdma_wc_receive() decrements the transport's Receive count for every completion before it dispatches a successful Receive to rpcrdma_reply_handler().
The handler must post a replacement Receive WR before returning unless ownership of the rep has moved elsewhere, as on the backchannel path.
Commit 2ae50ad68cd7 ("xprtrdma: Close window between waking RPC senders and posting Receives") moved the Receive refill out of rpcrdma_wc_receive(), where it had run ahead of every reply, into rpcrdma_reply_handler() so that the responder's credit grant could be parsed before reposting.
The bad-version and short-reply exits never reach that refill: they recycle the rep and return without calling rpcrdma_post_recvs(). A remote peer can therefore drain the client's posted Receive queue by sending a sustained stream of replies that are shorter than the fixed transport header or that carry an unrecognized RPC/RDMA version.
Each such reply consumes one posted Receive without replacing it. Once the queue empties, the peer's next Send finds no posted Receive and the transport stalls until reconnect.
Route both malformed-reply exits through the shared repost tail after recycling the rep, refilling against buf->rb_credits, the most recent accepted credit grant.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
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