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Fencer Vulns
medium 4.9

CVE-2020-35513 json

A flaw incorrect umask during file or directory modification in the Linux kernel NFS (network file system) functionality was found in the w…

published 2021-01-25 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-23180

cvss
4.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 71%
public exploits
0
none known

Summary

A flaw incorrect umask during file or directory modification in the Linux kernel NFS (network file system) functionality was found in the way user create and delete object using NFSv4.2 or newer if both simultaneously accessing the NFS by the other process that is not using new NFSv4.2. A user with access to the NFS could use this flaw to starve the resources causing denial of service.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 4.16.5-1

debian advisories DEBIAN-CVE-2020-35513

  • linux Ubuntu 18.04 LTS 4.15.0-23.25
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1010.10
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1014.14~16.04.1
  • linux-hwe Ubuntu 16.04 LTS 4.15.0-24.26~16.04.1
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1011.11
  • linux-azure Ubuntu 16.04 LTS 4.15.0-1013.13~16.04.2
  • linux-raspi2 Ubuntu 18.04 LTS 4.15.0-1012.13

ubuntu advisories UBUNTU-CVE-2020-35513

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 7 3.10.0-1160.15.2.el7
  • perf RHEL 7 3.10.0-1160.15.2.el7
  • bpftool RHEL 7 3.10.0-1160.15.2.el7
  • python-perf RHEL 7 3.10.0-1160.15.2.el7
  • kernel-kdump RHEL 7 3.10.0-1160.15.2.el7
  • kernel-tools RHEL 7 3.10.0-1160.15.2.el7
  • kernel-tools-libs RHEL 7 3.10.0-1160.15.2.el7
  • kernel-bootwrapper RHEL 7 3.10.0-1160.15.2.el7

red hat advisories RHSA-2021:0336RHSA-2021:0338

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-2020-35513 updated cvss 4.4

kernel: Nfsd failure to clear umask after processing an open or create

  • Red Hat Enterprise Linux 7 perf, kernel, kernel-alt, python-perf, kernel-kdump, kernel-tools, +3 more
    affected: no fix available
  • Red Hat Enterprise Linux Client (v. 7) perf 3.10.0-1160.15.2.el7, kernel 3.10.0-1160.15.2.el7, bpftool 3.10.0-1160.15.2.el7, python-perf 3.10.0-1160.15.2.el7, kernel-tools 3.10.0-1160.15.2.el7, kernel-tools-libs 3.10.0-1160.15.2.el7, +2 more Red Hat Enterprise Linux Client Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.15.2.el7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.15.2.el7
    fixed: vendor fix RHSA-2021:0336
  • Red Hat Enterprise Linux for Real Time (v. 7) kernel-rt 3.10.0-1160.15.2.rt56.1152.el7, kernel-rt-trace 3.10.0-1160.15.2.rt56.1152.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1160.15.2.rt56.1152.el7 Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt 3.10.0-1160.15.2.rt56.1152.el7, kernel-rt-kvm 3.10.0-1160.15.2.rt56.1152.el7, kernel-rt-trace 3.10.0-1160.15.2.rt56.1152.el7, kernel-rt-debug-kvm 3.10.0-1160.15.2.rt56.1152.el7, kernel-rt-trace-kvm 3.10.0-1160.15.2.rt56.1152.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1160.15.2.rt56.1152.el7
    fixed: vendor fix RHSA-2021:0338
  • Red Hat Enterprise Linux Server (v. 7) perf 3.10.0-1160.15.2.el7, kernel 3.10.0-1160.15.2.el7, bpftool 3.10.0-1160.15.2.el7, python-perf 3.10.0-1160.15.2.el7, kernel-kdump 3.10.0-1160.15.2.el7, kernel-tools 3.10.0-1160.15.2.el7, +7 more Red Hat Enterprise Linux Server Optional (v. 7) kernel-debuginfo-common-ppc64 3.10.0-1160.15.2.el7, kernel-debuginfo-common-x86_64 3.10.0-1160.15.2.el7, kernel-debuginfo-common-ppc64le 3.10.0-1160.15.2.el7 Red Hat Enterprise Linux Workstation (v. 7) perf 3.10.0-1160.15.2.el7, kernel 3.10.0-1160.15.2.el7, bpftool 3.10.0-1160.15.2.el7, python-perf 3.10.0-1160.15.2.el7, kernel-tools 3.10.0-1160.15.2.el7, kernel-tools-libs 3.10.0-1160.15.2.el7, +2 more Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.15.2.el7
    fixed: vendor fix RHSA-2021:0336
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux Client (v. 7) kernel-headers 3.10.0-1160.15.2.el7 Red Hat Enterprise Linux Server (v. 7) kernel-headers 3.10.0-1160.15.2.el7 Red Hat Enterprise Linux Workstation (v. 7) kernel-headers 3.10.0-1160.15.2.el7
    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

1.36% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.9 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Affected products

  • n/a kernel

Classification

Weakness
  • CWE-271 Privilege Dropping / Lowering Errors
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.