Description
In the Linux kernel, the following vulnerability has been resolved: NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr nfs4_decode_mp_ds_addr() decodes the r_netid and r_addr opaques of a netaddr4 from a GETDEVICEINFO multipath-DS body, then immediately calls strrchr(buf, '.') to locate the port separator. Both decodes use xdr_stream_decode_string_dup(), and the current code checks only "nlen < 0" / "rlen < 0" before dereferencing the returned string. When the on-wire opaque has length zero, xdr_stream_decode_opaque_inline() returns 0 and xdr_stream_decode_string_dup() falls through to its "*str = NULL; return ret" tail, leaving buf NULL with a return value of 0. The "< 0" check does not catch this, and the next line is strrchr(NULL, '.'), a kernel NULL pointer dereference reachable from any pNFS-flexfile client mounted against a malicious or compromised metadata server. Reject the zero-length cases explicitly so the decoder fails with -EBADMSG (treated as a malformed GETDEVICEINFO body) instead of panicking the client.
Affected products
linux: linux kernel
References7
- git.kernel.org/stable/c/012d37a568bfbb2c9686f03ade75560bc7139956 Patch
- git.kernel.org/stable/c/30aae62e50b4e074a90a9a5e15246548fbdc1182 Patch
- git.kernel.org/stable/c/41fe0f7b84f0cb822ae10ab08592996a592b2a25 Patch
- git.kernel.org/stable/c/427ab81a811dab4bca9d19f82eec5847ae42646e Patch
- git.kernel.org/stable/c/6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea Patch
- git.kernel.org/stable/c/76b94cbd32aacf36a641956385a852635c6802b9 Patch
- git.kernel.org/stable/c/c8e4e0c701d0192a2efb6df059c0f9e19678c23d Patch
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 45 · as of 14 November 2026
- CWE
- CWE-476
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