CVE-2018-20856

HIGHNVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.8Exploit: None knownExposed: 0

A fix is available — apply it.

An issue was discovered in the Linux kernel before 4.18.7. In block/blk-core.c, there is an __blk_drain_queue() use-after-free because a certain error case is mishandled.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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
Severity78% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
51%
KEV
Not listed

Published

July 26, 2019

Last Modified

November 21, 2024

References (48)

Patch Availability(11)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-image-virtual-hwe-16.04 (4.15.0.58.79) @ xenial2026-05-23ubuntu
ubuntulinux-image-aws-hwe (4.15.0.1047.47) @ xenial2026-05-23ubuntu
ubuntulinux-image-virtual-lts-xenial (4.4.0.161.169) @ xenial2026-05-23ubuntu
redhatkpatch-patch2020-03-03redhat
redhatkernel-0:3.10.0-957.46.1.el72020-03-03redhat
redhatkernel-0:3.10.0-862.48.1.el72020-02-19redhat
redhatkernel-0:3.10.0-693.62.1.el72020-01-14redhat
redhatkernel-rt-1:3.10.0-693.62.1.rt56.659.el6rt2020-01-14redhat
redhatkernel-alt-0:4.14.0-115.14.1.el7a2019-10-29redhat
redhatkernel-rt-0:3.10.0-1062.4.1.rt56.1027.el72019-10-16redhat
redhatkernel-0:3.10.0-1062.4.1.el72019-10-16redhat

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.

Affected Packages

(6 across 6 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux—4.18.8-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux—4.18.8-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux—4.18.8-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux—4.18.8-1—
Debian:8(1)
PackageVulnerable rangeFixed inDependents
linux-4.94.9.110-1~deb8u1, 4.9.144-3.1~deb8u1, 4.9.168-1~deb8u14.9.168-1+deb9u5~deb8u1—
Debian:9(1)
PackageVulnerable rangeFixed inDependents
linux4.9.107-1 ... 4.9.88-1~bpo8+1 (50 versions)4.9.168-1+deb9u5—

Weakness Classification(1)

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

All Vendor Advisories

(12)

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 8× in last 7d / 30× 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 130 total refreshes for this CVE.

  1. 2026-08-20 22:51 UTCEPSS rescore
  2. 2026-08-19 17:00 UTCEPSS rescore
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  22. 2026-07-12 20:07 UTCOSV refresh
  23. 2026-07-12 05:43 UTCEPSS rescore
  24. 2026-07-11 08:24 UTCEPSS rescore
  25. 2026-07-09 19:06 UTCEPSS rescore
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  49. 2026-06-24 05:29 UTCOSV refresh
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Frequently asked(5)

What is CVE-2018-20856?
CVE-2018-20856 is a high vulnerability published on July 26, 2019. An issue was discovered in the Linux kernel before 4.18.7. In block/blk-core.c, there is an blkdrainqueue() use-after-free because a certain error case is mishandled.
When was CVE-2018-20856 disclosed?
CVE-2018-20856 was first published in the National Vulnerability Database on July 26, 2019, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-20856 actively exploited?
CVE-2018-20856 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 49.3% of all scored CVEs.
What is the CVSS score of CVE-2018-20856?
CVE-2018-20856 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2018-20856?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-20856, 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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