CVE-2020-27170 — Observable Discrepancy in Canonical Ubuntu Linux

Triage

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

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

• Documented patch — cdn.kernel.org (NIST National Vulnerability Database)
• Documented patch — git.kernel.org (NIST National Vulnerability Database)
• Documented patch — www.openwall.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora…).
2. Apply the fixed version or the patch documented under Remediation.
3. Search available logs for exploit probes matching the vulnerability class (info disclosure), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

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

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-203 · Observable Discrepancy

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.57%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
• Look for anomalous data read/export volumes and access to sensitive records.

Timeline

What happened to this CVE, newest first.

• 2026
• SSVC assessment updated
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Record published
  Oct 13, 2026
• Fix documented
  Oct 13, 2026 · NIST National Vulnerability Database
• CVSS changed · 4.7
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · → Modified
  Oct 13, 2026 · NIST National Vulnerability Database
• Record created in this database
  Oct 13, 2026 · NIST National Vulnerability Database
• 2021
• CVE published
  Mar 20, 2021 · mitre

Source activity

Repeated readings are counted rather than listed.

• 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

9 on the record

• cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.8
  Patch, Vendor Advisory, x_refsource_MISC, NIST National Vulnerability Database
• git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/
  Patch, Vendor Advisory, x_refsource_MISC, NIST National Vulnerability Database
• www.openwall.com/lists/oss-security/2021/03/19/2
  Mailing List, Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T2S3
  vendor-advisory, x_refsource_FEDORA, NIST National Vulnerability Database
• lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FB6L
  vendor-advisory, x_refsource_FEDORA, NIST National Vulnerability Database
• packetstormsecurity.com/files/162117/Kernel-Live-Patch-Security-Notice-LSN-0075-1.html
  Third Party Advisory, VDB Entry, x_refsource_MISC, NIST National Vulnerability Database
• www.openwall.com/lists/oss-security/2021/03/24/4
  Mailing List, Third Party Advisory, mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QRTP
  vendor-advisory, x_refsource_FEDORA, NIST National Vulnerability Database
• lists.debian.org/debian-lts-announce/2021/03/msg00035.html
  Mailing List, Third Party Advisory, mailing-list, x_refsource_MLIST, NIST National Vulnerability Database

Elsewhere on this site

Related CVEs (same products)

• Medium CVE-2026-98164 KVM: x86/mmu: Check write tracking in all address spaces 16d
• High CVE-2026-98163 cgroup: Avoid iteration of dying tasks with zero refcount 19d
• Medium CVE-2026-98162 smb/server: fix tree connection leak in smb2_tree_connect() 20d
• Medium CVE-2026-98160 In the Linux kernel, the following vulnerability has been resolved: staging: rtl8723bs… 20d
• Medium CVE-2026-98161 Improper Check for Unusual or Exceptional Conditions in Linux Linux Kernel 20d
• Medium CVE-2026-100079 Missing Release of Resource after Effective Lifetime in Linux Linux Kernel 20d

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.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2020-27170 is "Observable Discrepancy in Canonical Ubuntu Linux", rated Medium. It affects Ubuntu Linux (Canonical); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.7 describes technical severity. EPSS 0.57% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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