🛡️ CVE-2026-53391 on Ubuntu — linux
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.
Distribution advisory
This page covers CVE-2026-53391 as tracked by Ubuntu, for the package linux. No fixed version has been recorded for this distribution yet.
How this vulnerability can be exploited
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.
Affected software
UBUNTU-CVE-2026-53391 is recorded against 162 packages.
- linux
- linux-allwinner-5.19
- linux-aws
- linux-aws-5.0
- linux-aws-5.11
- linux-aws-5.13
- linux-aws-5.15
- linux-aws-5.19
- linux-aws-5.3
- linux-aws-5.4
- linux-aws-5.8
- linux-aws-6.14
- linux-aws-6.17
- linux-aws-6.2
- linux-aws-6.5
- linux-aws-6.8
- linux-aws-fips
- linux-aws-hwe
- linux-azure
- linux-azure-4.15
- linux-azure-5.11
- linux-azure-5.13
- linux-azure-5.15
- linux-azure-5.19
Show the remaining 138 packages
- linux-azure-5.3
- linux-azure-5.4
- linux-azure-5.8
- linux-azure-6.11
- linux-azure-6.14
- linux-azure-6.17
- linux-azure-6.2
- linux-azure-6.5
- linux-azure-6.8
- linux-azure-edge
- linux-azure-fde
- linux-azure-fde-5.15
- linux-azure-fde-5.19
- linux-azure-fde-6.14
- linux-azure-fde-6.17
- linux-azure-fde-6.2
- linux-azure-fde-6.8
- linux-azure-fips
- linux-azure-nvidia
- linux-azure-nvidia-6.14
- linux-bluefield
- linux-fips
- linux-gcp
- linux-gcp-4.15
- linux-gcp-5.11
- linux-gcp-5.13
- linux-gcp-5.15
- linux-gcp-5.19
- linux-gcp-5.3
- linux-gcp-5.4
- linux-gcp-5.8
- linux-gcp-6.11
- linux-gcp-6.14
- linux-gcp-6.17
- linux-gcp-6.2
- linux-gcp-6.5
- linux-gcp-6.8
- linux-gcp-fips
- linux-gke
- linux-gke-4.15
- linux-gke-5.15
- linux-gke-5.4
- linux-gkeop
- linux-gkeop-5.15
- linux-gkeop-5.4
- linux-hwe
- linux-hwe-5.11
- linux-hwe-5.13
- linux-hwe-5.15
- linux-hwe-5.19
- linux-hwe-5.4
- linux-hwe-5.8
- linux-hwe-6.11
- linux-hwe-6.14
- linux-hwe-6.17
- linux-hwe-6.2
- linux-hwe-6.5
- linux-hwe-6.8
- linux-hwe-7.0
- linux-hwe-edge
- linux-ibm
- linux-ibm-5.15
- linux-ibm-5.4
- linux-ibm-6.8
- linux-intel-5.13
- linux-intel-iot-realtime
- linux-intel-iotg
- linux-intel-iotg-5.15
- linux-iot
- linux-kvm
- linux-lowlatency
- linux-lowlatency-hwe-5.15
- linux-lowlatency-hwe-5.19
- linux-lowlatency-hwe-6.11
- linux-lowlatency-hwe-6.2
- linux-lowlatency-hwe-6.5
- linux-lowlatency-hwe-6.8
- linux-lts-xenial
- linux-nvidia
- linux-nvidia-6.11
- linux-nvidia-6.17
- linux-nvidia-6.2
- linux-nvidia-6.5
- linux-nvidia-6.8
- linux-nvidia-7.0
- linux-nvidia-bos
- linux-nvidia-lowlatency
- linux-nvidia-tegra
- linux-nvidia-tegra-5.15
- linux-nvidia-tegra-igx
- linux-oem
- linux-oem-5.10
- linux-oem-5.13
- linux-oem-5.14
- linux-oem-5.17
- linux-oem-5.6
- linux-oem-6.0
- linux-oem-6.1
- linux-oem-6.11
- linux-oem-6.14
- linux-oem-6.17
- linux-oem-6.5
- linux-oem-6.8
- linux-oem-7.0
- linux-oracle
- linux-oracle-5.0
- linux-oracle-5.11
- linux-oracle-5.13
- linux-oracle-5.15
- linux-oracle-5.3
- linux-oracle-5.4
- linux-oracle-5.8
- linux-oracle-6.14
- linux-oracle-6.17
- linux-oracle-6.5
- linux-oracle-6.8
- linux-raspi
- linux-raspi-5.4
- linux-raspi-realtime
- linux-raspi2
- linux-realtime
- linux-realtime-6.14
- linux-realtime-6.17
- linux-realtime-6.8
- linux-riscv
- linux-riscv-5.11
- linux-riscv-5.15
- linux-riscv-5.19
- linux-riscv-5.8
- linux-riscv-6.14
- linux-riscv-6.17
- linux-riscv-6.5
- linux-riscv-6.8
- linux-starfive-5.19
- linux-starfive-6.2
- linux-starfive-6.5
- linux-xilinx
- linux-xilinx-zynqmp
Timeline and source
Published on 19 July 2026 and last revised on 11 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
References
ubuntu.com (Report)
www.cve.org (Report)
git.kernel.org (Report)
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| linux | — | — |
| linux-allwinner-5.19 | — | — |
| linux-aws | — | — |
| linux-aws-5.0 | — | — |
| linux-aws-5.11 | — | — |
| linux-aws-5.13 | — | — |
| linux-aws-5.15 | — | — |
| linux-aws-5.19 | — | — |
| linux-aws-5.3 | — | — |
| linux-aws-5.4 | — | — |
| linux-aws-5.8 | — | — |
| linux-aws-6.14 | — | — |
| linux-aws-6.17 | — | — |
| linux-aws-6.2 | — | — |
| linux-aws-6.5 | — | — |
| linux-aws-6.8 | — | — |
| linux-aws-fips | — | — |
| linux-aws-hwe | — | — |
| linux-azure | — | — |
| linux-azure-4.15 | — | — |
| linux-azure-5.11 | — | — |
| linux-azure-5.13 | — | — |
| linux-azure-5.15 | — | — |
| linux-azure-5.19 | — | — |
| linux-azure-5.3 | — | — |
| linux-azure-5.4 | — | — |
| linux-azure-5.8 | — | — |
| linux-azure-6.11 | — | — |
| linux-azure-6.14 | — | — |
| linux-azure-6.17 | — | — |
| linux-azure-6.2 | — | — |
| linux-azure-6.5 | — | — |
| linux-azure-6.8 | — | — |
| linux-azure-edge | — | — |
| linux-azure-fde | — | — |
| linux-azure-fde-5.15 | — | — |
| linux-azure-fde-5.19 | — | — |
| linux-azure-fde-6.14 | — | — |
| linux-azure-fde-6.17 | — | — |
| linux-azure-fde-6.2 | — | — |
| linux-azure-fde-6.8 | — | — |
| linux-azure-fips | — | — |
| linux-azure-nvidia | — | — |
| linux-azure-nvidia-6.14 | — | — |
| linux-bluefield | — | — |
| linux-fips | — | — |
| linux-gcp | — | — |
| linux-gcp-4.15 | — | — |
| linux-gcp-5.11 | — | — |
| linux-gcp-5.13 | — | — |
| linux-gcp-5.15 | — | — |
| linux-gcp-5.19 | — | — |
| linux-gcp-5.3 | — | — |
| linux-gcp-5.4 | — | — |
| linux-gcp-5.8 | — | — |
| linux-gcp-6.11 | — | — |
| linux-gcp-6.14 | — | — |
| linux-gcp-6.17 | — | — |
| linux-gcp-6.2 | — | — |
| linux-gcp-6.5 | — | — |
| linux-gcp-6.8 | — | — |
| linux-gcp-fips | — | — |
| linux-gke | — | — |
| linux-gke-4.15 | — | — |
| linux-gke-5.15 | — | — |
| linux-gke-5.4 | — | — |
| linux-gkeop | — | — |
| linux-gkeop-5.15 | — | — |
| linux-gkeop-5.4 | — | — |
| linux-hwe | — | — |
| linux-hwe-5.11 | — | — |
| linux-hwe-5.13 | — | — |
| linux-hwe-5.15 | — | — |
| linux-hwe-5.19 | — | — |
| linux-hwe-5.4 | — | — |
| linux-hwe-5.8 | — | — |
| linux-hwe-6.11 | — | — |
| linux-hwe-6.14 | — | — |
| linux-hwe-6.17 | — | — |
| linux-hwe-6.2 | — | — |
| linux-hwe-6.5 | — | — |
| linux-hwe-6.8 | — | — |
| linux-hwe-7.0 | — | — |
| linux-hwe-edge | — | — |
| linux-ibm | — | — |
| linux-ibm-5.15 | — | — |
| linux-ibm-5.4 | — | — |
| linux-ibm-6.8 | — | — |
| linux-intel-5.13 | — | — |
| linux-intel-iot-realtime | — | — |
| linux-intel-iotg | — | — |
| linux-intel-iotg-5.15 | — | — |
| linux-iot | — | — |
| linux-kvm | — | — |
| linux-lowlatency | — | — |
| linux-lowlatency-hwe-5.15 | — | — |
| linux-lowlatency-hwe-5.19 | — | — |
| linux-lowlatency-hwe-6.11 | — | — |
| linux-lowlatency-hwe-6.2 | — | — |
| linux-lowlatency-hwe-6.5 | — | — |
| linux-lowlatency-hwe-6.8 | — | — |
| linux-lts-xenial | — | — |
| linux-nvidia | — | — |
| linux-nvidia-6.11 | — | — |
| linux-nvidia-6.17 | — | — |
| linux-nvidia-6.2 | — | — |
| linux-nvidia-6.5 | — | — |
| linux-nvidia-6.8 | — | — |
| linux-nvidia-7.0 | — | — |
| linux-nvidia-bos | — | — |
| linux-nvidia-lowlatency | — | — |
| linux-nvidia-tegra | — | — |
| linux-nvidia-tegra-5.15 | — | — |
| linux-nvidia-tegra-igx | — | — |
| linux-oem | — | — |
| linux-oem-5.10 | — | — |
| linux-oem-5.13 | — | — |
| linux-oem-5.14 | — | — |
| linux-oem-5.17 | — | — |
| linux-oem-5.6 | — | — |
| linux-oem-6.0 | — | — |
| linux-oem-6.1 | — | — |
| linux-oem-6.11 | — | — |
| linux-oem-6.14 | — | — |
| linux-oem-6.17 | — | — |
| linux-oem-6.5 | — | — |
| linux-oem-6.8 | — | — |
| linux-oem-7.0 | — | — |
| linux-oracle | — | — |
| linux-oracle-5.0 | — | — |
| linux-oracle-5.11 | — | — |
| linux-oracle-5.13 | — | — |
| linux-oracle-5.15 | — | — |
| linux-oracle-5.3 | — | — |
| linux-oracle-5.4 | — | — |
| linux-oracle-5.8 | — | — |
| linux-oracle-6.14 | — | — |
| linux-oracle-6.17 | — | — |
| linux-oracle-6.5 | — | — |
| linux-oracle-6.8 | — | — |
| linux-raspi | — | — |
| linux-raspi-5.4 | — | — |
| linux-raspi-realtime | — | — |
| linux-raspi2 | — | — |
| linux-realtime | — | — |
| linux-realtime-6.14 | — | — |
| linux-realtime-6.17 | — | — |
| linux-realtime-6.8 | — | — |
| linux-riscv | — | — |
| linux-riscv-5.11 | — | — |
| linux-riscv-5.15 | — | — |
| linux-riscv-5.19 | — | — |
| linux-riscv-5.8 | — | — |
| linux-riscv-6.14 | — | — |
| linux-riscv-6.17 | — | — |
| linux-riscv-6.5 | — | — |
| linux-riscv-6.8 | — | — |
| linux-starfive-5.19 | — | — |
| linux-starfive-6.2 | — | — |
| linux-starfive-6.5 | — | — |
| linux-xilinx | — | — |
| linux-xilinx-zynqmp | — | — |
References
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More UBUNTU CVE 2026 advisories
Browse all of UBUNTU CVE 2026 in the advisory index.
- UBUNTU-CVE-2026-53383
- UBUNTU-CVE-2026-53384
- UBUNTU-CVE-2026-53385
- UBUNTU-CVE-2026-53386
- UBUNTU-CVE-2026-53387
- UBUNTU-CVE-2026-53388
- UBUNTU-CVE-2026-53389
- UBUNTU-CVE-2026-53390
- UBUNTU-CVE-2026-53392
- UBUNTU-CVE-2026-53393
- UBUNTU-CVE-2026-53394
- UBUNTU-CVE-2026-53395
- UBUNTU-CVE-2026-53396
- UBUNTU-CVE-2026-53397
- UBUNTU-CVE-2026-53398
- UBUNTU-CVE-2026-53399
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