NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 14 fixed, 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-476.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 4.0 and later | 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 4.0 and later Fixed in 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3, 7.2 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 4.0 to before 5.15.211; 5.16 to before 6.1.177; 6.2 to before 6.6.144; 6.7 to before 6.12.95; 6.13 to before 6.18.38; 6.19 to before 7.1.3 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.0 to before 5.15.211; 5.16 to before 6.1.177; 6.2 to before 6.6.144; 6.7 to before 6.12.95; 6.13 to before 6.18.38; 6.19 to before 7.1.3 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3, 7.2
Red Hat 4 advisories
- RHSA-2026:63129 Released 2026-09-04 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.44.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.44.1.el9_8, kernel-64k-devel-5.14.0-687.44.1.el9_8 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.44.1.el9_8, kernel-64k-5.14.0-687.44.1.el9_8, kernel-64k-core-5.14.0-687.44.1.el9_8 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.44.1.el9_8, libperf-5.14.0-687.44.1.el9_8
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.44.1.el9_8, kernel-rt-64k-5.14.0-687.44.1.el9_8, kernel-rt-64k-core-5.14.0-687.44.1.el9_8 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.44.1.el9_8, kernel-rt-core-5.14.0-687.44.1.el9_8, kernel-rt-debug-5.14.0-687.44.1.el9_8 +9
- RHSA-2026:63014 Released 2026-09-03 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.159.1.el8_10, kernel-4.18.0-553.159.1.el8_10, kernel-abi-stablelists-4.18.0-553.159.1.el8_10 +19
- Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.159.1.el8_10
- RHSA-2026:63013 Released 2026-09-03 · Red Hat rating Importantkernel-rt security, bug fix, and enhancement update
- Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-core-4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-debug-4.18.0-553.159.1.rt7.500.el8_10 +9
- Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-core-4.18.0-553.159.1.rt7.500.el8_10, kernel-rt-debug-4.18.0-553.159.1.rt7.500.el8_10 +7
Show 1 more Red Hat advisories
- RHSA-2026:61887 Released 2026-09-01 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.50.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.50.1.el10_2, kernel-64k-devel-6.12.0-211.50.1.el10_2 +12
- Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.50.1.el10_2, kernel-64k-6.12.0-211.50.1.el10_2, kernel-64k-core-6.12.0-211.50.1.el10_2 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.50.1.el10_2, libperf-6.12.0-211.50.1.el10_2
- Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.50.1.el10_2, kernel-rt-64k-6.12.0-211.50.1.el10_2, kernel-rt-64k-core-6.12.0-211.50.1.el10_2 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.50.1.el10_2, kernel-rt-core-6.12.0-211.50.1.el10_2, kernel-rt-debug-6.12.0-211.50.1.el10_2 +9
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:61887 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:63129 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:61887 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2026:63014 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:63129 |
| Red Hat Enterprise Linux CRB (v. 8) | Fixed | RHSA-2026:63014 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:61887 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:63129 |
| Red Hat Enterprise Linux NFV (v. 8) | Fixed | RHSA-2026:63013 |
| Red Hat Enterprise Linux RT (v. 8) | Fixed | RHSA-2026:63013 |
| Red Hat Enterprise Linux Real Time (v. 10) | Fixed | RHSA-2026:61887 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2026:63129 |
| Red Hat Enterprise Linux Real Time for NFV (v. 10) | Fixed | RHSA-2026:61887 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2026:63129 |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-53391
- 2026-10-03 Alias added: GHSA-72jx-g4pr-67hm
- 2026-10-13 Affected versions changed · Red Hat
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-19 Weakness changed · CISA ADP
- 2026-11-06 CVSS score changed · Red Hat
References
Patch 7
- https://git.kernel.org/stable/c/76b94cbd32aacf36a641956385a852635c6802b9
- https://git.kernel.org/stable/c/c8e4e0c701d0192a2efb6df059c0f9e19678c23d
- https://git.kernel.org/stable/c/6c344fff2feff9d4d716d8e4ad40e9b5040ee5ea
- https://git.kernel.org/stable/c/427ab81a811dab4bca9d19f82eec5847ae42646e
- https://git.kernel.org/stable/c/012d37a568bfbb2c9686f03ade75560bc7139956
- https://git.kernel.org/stable/c/30aae62e50b4e074a90a9a5e15246548fbdc1182
- https://git.kernel.org/stable/c/41fe0f7b84f0cb822ae10ab08592996a592b2a25
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Sources
- CVE-2026-53391 · CVE Program
- CVE-2026-53391 · NVD
- FIRST EPSS
- GHSA-72jx-g4pr-67hm · GitHub Advisory Database · CC BY 4.0
- CVE-2026-53391 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences