CVE-2021-28715

Advisory lineage Upstream: 0 Downstream: 30
Modified
Published: 06 Jan 2022, 17:06
Last modified:22 May 2025, 18:34

Vulnerability Summary

Overall Risk (default)
medium
26/100
CVSS Score
6.5 MEDIUM
v3.1 (cve.org)
EPSS Score
0.24% LOW
0% probability +0.23%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

06 Jan 2022, 17:06
Published
Vulnerability first disclosed
22 May 2025, 18:34
Last Modified
Vulnerability information updated

Description

Guest can force Linux netback driver to hog large amounts of kernel memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Incoming data packets for a guest in the Linux kernel's netback driver are buffered until the guest is ready to process them. There are some measures taken for avoiding to pile up too much data, but those can be bypassed by the guest: There is a timeout how long the client side of an interface can stop consuming new packets before it is assumed to have stalled, but this timeout is rather long (60 seconds by default). Using a UDP connection on a fast interface can easily accumulate gigabytes of data in that time. (CVE-2021-28715) The timeout could even never trigger if the guest manages to have only one free slot in its RX queue ring page and the next package would require more than one free slot, which may be the case when using GSO, XDP, or software hashing. (CVE-2021-28714)

CVSS Metrics

  • v3.1•MEDIUM•Score: 6.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
  • v2.0•LOW•Score: 2.1AV:L/AC:L/Au:N/C:N/I:N/A:P

EPSS Trends

Current EPSS score: 0.24%• Percentile: 48%

Techniques & Countermeasures

  • CWE-770•Allocation of Resources Without Limits or Throttling

    The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

Affected Systems

  • debian•debian_linux

    9.0 | 10.0 | 11.0

  • linux•linux_kernel

    < 5.15.0

References (5)