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HIGHpublic exploit

CVE-2021-3492

CVE-2021-3492 — Ubuntu linux kernel shiftfs file system double free vulnerability

Shiftfs, an out-of-tree stacking file system included in Ubuntu Linux kernels, did not properly handle faults occurring during copy_from_user() correctly. These could lead to either a double-free situation or memory not being freed at all. An attacker could use this to cause a denial of service (kernel memory exhaustion) or gain privileges via executing arbitrary code. AKA ZDI-CAN-13562.

Published Updated Sources: cvelistV5, canonical

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Exploit code

public exploit, none observed

EPSS

2%

chance of exploitation in 30 days

Affects

ubuntu

linux_kernel

CVSS base

8.8

HIGH

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

ubuntu

Products (1)

linux kernel

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
8.8CVSS 3.1HIGH——cvelistV5

Weakness & attack patterns

  • CWE-415
  • CWE-401

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Indexed by

poc in github

References

6 on the record

Elsewhere on this site

  • ubuntuevery CVE for this vendor
  • CWE-415other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.