Skip to content
Fencer Vulns
high 7.5

CVE-2021-38201 json

net/sunrpc/xdr.c in the Linux kernel before 5.13.4 allows remote attackers to cause a denial of service (xdr_set_page_base slab-out-of-boun…

published 2021-08-08 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-24659

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.4%
EPSS 3.4% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

net/sunrpc/xdr.c in the Linux kernel before 5.13.4 allows remote attackers to cause a denial of service (xdr_set_page_base slab-out-of-bounds access) by performing many NFS 4.2 READ_PLUS operations.

Patch / fix

  • linux linux_kernel 5.12.19, 5.13.4
  • linux-aws-5.11 Ubuntu 20.04 LTS 5.11.0-1019.20~20.04.1
  • linux-gcp-5.11 Ubuntu 20.04 LTS 5.11.0-1020.22~20.04.1
  • linux-hwe-5.11 Ubuntu 20.04 LTS 5.11.0-37.41~20.04.2
  • linux-oem-5.13 Ubuntu 20.04 LTS 5.13.0-1014.18
  • linux-azure-5.11 Ubuntu 20.04 LTS 5.11.0-1017.18~20.04.1
  • linux-riscv-5.11 Ubuntu 20.04 LTS 5.11.0-1020.21~20.04.1
  • linux-oracle-5.11 Ubuntu 20.04 LTS 5.11.0-1019.20~20.04.1

ubuntu advisories UBUNTU-CVE-2021-38201

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 8 4.18.0-305.17.1.el8_4
  • perf RHEL 8 4.18.0-305.17.1.el8_4
  • bpftool RHEL 8 4.18.0-305.17.1.el8_4
  • kernel-core RHEL 8 4.18.0-305.17.1.el8_4
  • kernel-tools RHEL 8 4.18.0-305.17.1.el8_4
  • python3-perf RHEL 8 4.18.0-305.17.1.el8_4
  • kernel-modules RHEL 8 4.18.0-305.17.1.el8_4
  • kernel-zfcpdump RHEL 8 4.18.0-305.17.1.el8_4

red hat advisories RHSA-2021:3447RHSA-2021:3440

  • kernel Rocky Linux 8 4.18.0-305.17.1.el8_4
  • kernel-rt Rocky Linux 8 4.18.0-305.17.1.rt7.89.el8_4

rocky linux advisories RLSA-2021:3447RLSA-2021:3440

  • kernel CBL-Mariner 2.0 5.10.78.1-1

azure linux advisories AZL-6585

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-38201 updated cvss 7.5

kernel: slab-out-of-bounds access in xdr_set_page_base() in net/sunrpc/xdr.c

  • Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-305.17.1.el8_4, kernel-debuginfo-common-aarch64 4.18.0-305.17.1.el8_4, kernel-debuginfo-common-ppc64le 4.18.0-305.17.1.el8_4 Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-305.17.1.el8_4, kernel 4.18.0-305.17.1.el8_4, bpftool 4.18.0-305.17.1.el8_4, kernel-core 4.18.0-305.17.1.el8_4, kernel-tools 4.18.0-305.17.1.el8_4, python3-perf 4.18.0-305.17.1.el8_4, +15 more
    fixed: vendor fix RHSA-2021:3447
  • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt 4.18.0-305.17.1.rt7.89.el8_4, kernel-rt-core 4.18.0-305.17.1.rt7.89.el8_4, kernel-rt-modules 4.18.0-305.17.1.rt7.89.el8_4, kernel-rt-debug-core 4.18.0-305.17.1.rt7.89.el8_4, kernel-rt-debug-modules 4.18.0-305.17.1.rt7.89.el8_4, kernel-rt-modules-extra 4.18.0-305.17.1.rt7.89.el8_4, +2 more Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt 4.18.0-305.17.1.rt7.89.el8_4, kernel-rt-kvm 4.18.0-305.17.1.rt7.89.el8_4, kernel-rt-core 4.18.0-305.17.1.rt7.89.el8_4, kernel-rt-modules 4.18.0-305.17.1.rt7.89.el8_4, kernel-rt-debug-kvm 4.18.0-305.17.1.rt7.89.el8_4, kernel-rt-debug-core 4.18.0-305.17.1.rt7.89.el8_4, +4 more
    fixed: vendor fix RHSA-2021:3440
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.36% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.