CVE-2026-53391

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-07-19 12:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-19 20:19 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.5% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-07-19 12:16 UTC

Last modified

2026-10-19 20:19 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-476 · NULL pointer dereference

Record status

Modified

Affected

• Linux Kernel < 5.15.211
• Linux Kernel < 6.1.177
• Linux Kernel < 6.6.144
• Linux Kernel < 6.12.95
• Linux Kernel < 6.18.38
• Linux Kernel < 7.1.3

Attack profile CVSS 3.1 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-53391.md and follow it. Check whether this project is affected by CVE-2026-53391. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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