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Fencer Vulns
high 7.1

CVE-2021-3506 json

An out-of-bounds (OOB) memory access flaw was found in fs/f2fs/node.c in the f2fs module in the Linux kernel in versions before 5.12.0-rc4.

published 2021-04-19 5 y ago modified 2026-09-01 2 mo ago also EUVD-2021-26825

cvss
7.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

An out-of-bounds (OOB) memory access flaw was found in fs/f2fs/node.c in the f2fs module in the Linux kernel in versions before 5.12.0-rc4. A bounds check failure allows a local attacker to gain access to out-of-bounds memory leading to a system crash or a leak of internal kernel information. The highest threat from this vulnerability is to system availability.

Patch / fix

  • linux linux_kernel 4.19.191, 5.4.118, 5.10.36, 5.11.20, 5.12.3
  • linux Debian 14, Debian 13, Debian 12 5.10.38-1

debian advisories DEBIAN-CVE-2021-3506

  • linux Ubuntu 18.04 LTS 4.15.0-173.182
  • linux Ubuntu 20.04 LTS 5.4.0-77.86
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1124.133
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1051.53
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1046.49
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1046.48
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1110.113
  • linux-kvm Ubuntu 20.04 LTS 5.4.0-1041.42

ubuntu advisories UBUNTU-CVE-2021-3506

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 CBL-Mariner 2.0 5.10.78.1-1

azure linux advisories AZL-6571

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

  • linux-lts Arch Linux 5.10.36-1
  • linux Arch Linux 5.12.3.arch1-1
  • linux-zen Arch Linux 5.12.3.zen1-1
  • linux-hardened Arch Linux 5.11.20.hardened1-1

arch linux advisories AVG-1942AVG-1952AVG-1953AVG-1954

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-2021-3506 updated cvss 8.1

kernel: Out of bounds memory access bug in get_next_net_page() in fs/f2fs/node.c

  • 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, kernel-alt, python-perf, +9 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 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

cisa ICSA-24-319-06 updated cvss 7.1

Siemens SCALANCE M-800 Family

  • Siemens RUGGEDCOM RM1224 LTE(4G) EU (6GK6108-4AM00-2BA2) <V8.2 Siemens RUGGEDCOM RM1224 LTE(4G) NAM (6GK6108-4AM00-2DA2) <V8.2 Siemens SCALANCE M804PB (6GK5804-0AP00-2AA2) <V8.2 Siemens SCALANCE M812-1 ADSL-Router (6GK5812-1AA00-2AA2) <V8.2 Siemens SCALANCE M812-1 ADSL-Router (6GK5812-1BA00-2AA2) <V8.2 Siemens SCALANCE M816-1 ADSL-Router (6GK5816-1AA00-2AA2) <V8.2
    +20 more products
    Siemens SCALANCE M816-1 ADSL-Router (6GK5816-1BA00-2AA2) <V8.2 Siemens SCALANCE M826-2 SHDSL-Router (6GK5826-2AB00-2AB2) <V8.2 Siemens SCALANCE M874-2 (6GK5874-2AA00-2AA2) <V8.2 Siemens SCALANCE M874-3 (6GK5874-3AA00-2AA2) <V8.2 Siemens SCALANCE M874-3 3G-Router (CN) (6GK5874-3AA00-2FA2) <V8.2 Siemens SCALANCE M876-3 (6GK5876-3AA02-2BA2) <V8.2 Siemens SCALANCE M876-3 (ROK) (6GK5876-3AA02-2EA2) <V8.2 Siemens SCALANCE M876-4 (6GK5876-4AA10-2BA2) <V8.2 Siemens SCALANCE M876-4 (EU) (6GK5876-4AA00-2BA2) <V8.2 Siemens SCALANCE M876-4 (NAM) (6GK5876-4AA00-2DA2) <V8.2 Siemens SCALANCE MUM853-1 (A1) (6GK5853-2EA10-2AA1) <V8.2 Siemens SCALANCE MUM853-1 (B1) (6GK5853-2EA10-2BA1) <V8.2 Siemens SCALANCE MUM853-1 (EU) (6GK5853-2EA00-2DA1) <V8.2 Siemens SCALANCE MUM856-1 (A1) (6GK5856-2EA10-3AA1) <V8.2 Siemens SCALANCE MUM856-1 (B1) (6GK5856-2EA10-3BA1) <V8.2 Siemens SCALANCE MUM856-1 (CN) (6GK5856-2EA00-3FA1) <V8.2 Siemens SCALANCE MUM856-1 (EU) (6GK5856-2EA00-3DA1) <V8.2 Siemens SCALANCE MUM856-1 (RoW) (6GK5856-2EA00-3AA1) <V8.2 Siemens SCALANCE S615 EEC LAN-Router (6GK5615-0AA01-2AA2) <V8.2 Siemens SCALANCE S615 LAN-Router (6GK5615-0AA00-2AA2) <V8.2
    affected: fixed in V8.2 support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
NVD 2.0 5.6 AV:L/AC:L/Au:N/C:P/I:N/A:C

Affected products

  • n/a kernel

Classification

Weakness
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.