CVE-2021-28715

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2022-01-07. NVD baseline CVSS 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.5Exploit: NoneExposed: 0

A fix is available — apply it.

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 v3
6.5
EG Score
6.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
25.6%
KEV
Not listed

Published

January 6, 2022

Last Modified

May 22, 2025

References (10)

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-buildinfo-5.14.0-1022-oem (5.14.0-1022.24) @ focal2026-05-26ubuntu
ubuntulinux-tools-4.15.0-1131-azure (4.15.0-1131.144~16.04.1) @ xenial2026-05-26ubuntu
ubuntulinux-image-unsigned-5.13.0-37-lowlatency (5.13.0-37.42) @ impish2026-05-26ubuntu
ubuntulinux-headers-azure-fde (5.4.0.1073.76+cvm1.19) @ focal2026-05-26ubuntu
ubuntulinux-headers-bluefield (5.4.0.1032.33) @ focal2026-05-26ubuntu
ubuntulinux-tools-5.13.0-1021-azure (5.13.0-1021.24~20.04.1) @ focal2026-05-26ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(7)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 14× in last 7d / 51× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 103 total refreshes for this CVE.

  1. 2026-07-23 01:59 UTCEG score recompute
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Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-28715?
CVE-2021-28715 is a medium vulnerability published on January 6, 2022. 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…
When was CVE-2021-28715 disclosed?
CVE-2021-28715 was first published in the National Vulnerability Database on January 6, 2022, with the most recent update on May 22, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-28715 actively exploited?
CVE-2021-28715 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 25.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-28715?
CVE-2021-28715 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2021-28715?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-28715, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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