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Fencer Vulns
high 7.8

CVE-2021-1048 kev in the critical feed json

In ep_loop_check_proc of eventpoll.c, there is a possible way to corrupt memory due to a use after free.

published 2021-12-15 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-6515

cvss
7.8
version 3.1, CNA
cisa kev
Exploited
added 2022-05-23
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 64%
public exploits
0
none known

Summary

In ep_loop_check_proc of eventpoll.c, there is a possible way to corrupt memory due to a use after free. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-204573007References: Upstream kernel

Patch / fix

cisa required action Apply updates per vendor instructions.

  • linux Debian 14, Debian 13, Debian 12 5.8.10-1

debian advisories DEBIAN-CVE-2021-1048

  • linux Ubuntu 18.04 LTS 4.15.0-126.129
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1088.93
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1088.101~16.04.1
  • linux-hwe Ubuntu 16.04 LTS 4.15.0-126.129~16.04.1
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1079.81
  • linux-azure Ubuntu 16.04 LTS 4.15.0-1100.111~16.04.1
  • linux-oracle Ubuntu 16.04 LTS 4.15.0-1059.65~16.04.1
  • linux-oracle Ubuntu 18.04 LTS 4.15.0-1059.65

ubuntu advisories UBUNTU-CVE-2021-1048

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

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-2021-1048 updated cvss 7.8

kernel: Use After Free in epoll_loop_check_proc() which could result in a local privilege escalation

  • 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 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 Red Hat Virtualization 4 redhat-virtualization-host-image-update
    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

Timeline

  1. 0-day patched (Project Zero)
  2. Published
  3. Added to CISA KEV
  4. CISA patch deadline
  5. CISA SSVC: exploitation active

Known exploited

Added
4 y ago
Patch by
2022-06-13 (4 y ago)
Ransomware
Not known
Required action
Apply updates per vendor instructions.
Vendor, product
Android, Kernel
CISA name
Android Kernel Use-After-Free Vulnerability

Zero-day

Detected in real attacks while still unknown to the vendor and the public, per Google Project Zero's 0day In-the-Wild tracker.

Patched
2021-11-06
Details
project zero root cause analysis

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
no
Technical impact
total
Assessed
21 mo ago

Exploit prediction

1.06% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C

Affected products

  • n/a Android

Classification

Weakness

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.