SUNRPC: double free xprt_ctxt while still in use

Summary

In the Linux kernel, the following vulnerability has been resolved: SUNRPC: double free xprt_ctxt while still in use When an RPC request is deferred, the rq_xprt_ctxt pointer is moved out of the svc_rqst into the svc_deferred_req. When the deferred request is revisited, the pointer is copied into the new svc_rqst - and also remains in the svc_deferred_req. In the (rare?) case that the request is deferred a second time, the old svc_deferred_req is reused - it still has all the correct content. However in that case the rq_xprt_ctxt pointer is NOT cleared so that when xpo_release_xprt is called, the ctxt is freed (UDP) or possible added to a free list (RDMA). When the deferred request is revisited for a second time, it will reference this ctxt which may be invalid, and the free the object a second time which is likely to oops. So change svc_defer() to always clear rq_xprt_ctxt, and assert that the value is now stored in the svc_deferred_req.

Timeline

1. Dec 30, 2025, 12:16 PM UTCCVE published
2. Oct 15, 2026, 9:39 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: total

3. Oct 15, 2026, 9:41 PM UTCRecord last updated

Affected versions

• Linux Linux

  From f5e13d700a4d40ccde3d36e383f9247dcb3c1d2d · fixed in 7851771789e87108a92697194105ef0c9307dc5e; From 773f91b2cf3f52df0d7508fdbf60f37567cdaee4 · fixed in fd86534872f445f54dc01e7db001e25eadf063a8; From 773f91b2cf3f52df0d7508fdbf60f37567cdaee4 · fixed in e0c648627322a4c7e018e5c7f837c3c03e297dbb; From 773f91b2cf3f52df0d7508fdbf60f37567cdaee4 · fixed in eb8d3a2c809abd73ab0a060fe971d6b9019aa3c1; From 5.15.35 · fixed in 5.15.113; From 5.17.4 · fixed in 5.18

• Linux Linux

  5.18

• KernelLinux

  fixed in 5.15.113; From 5.16.0 · fixed in 6.1.30; From 5.18.0 · fixed in 6.3.4

References 4