CVE-2026-53391: 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 a

highCVSS 7.5CVE-2026-53391

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.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: high — CVSS 7.5
Published: 2026-07-19
Last updated: 2026-07-20
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-53391

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-533910.52% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 41% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-53391	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

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