CVE Intelligence
Medium Info disclosure exploit reference

CVE-2018-5407 — Observable Discrepancy in Canonical Ubuntu Linux

Simultaneous Multi-threading (SMT) in processors can enable local users to exploit software vulnerable to timing attacks via a side-channel timing attack on 'port contention'.

Published Nov 15, 2018 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: certcc

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

Exploit-DB · 1
How the score was calculated
  • Public exploit/PoC (exploitdb)+8
  • EPSS 3.4% (30-day exploitation probability)+13
  • Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

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

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
3.42%
ahead of 89% of scored CVEs · Oct 15, 2026
Affects
Canonical
Ubuntu Linux and 19 more
CVSS base
4.7
Medium · 1 source(s)

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.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

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

  • Documented patch — www.oracle.com (NIST National Vulnerability Database)
  • Documented patch — www.oracle.com (NIST National Vulnerability Database)
  • Documented patch — www.oracle.com (NIST National Vulnerability Database)
  • Documented patch — www.oracle.com (NIST National Vulnerability Database)
  • Documented patch — www.oracle.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, Nodejs Node.js…).
  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.

VendorProductVersionsStatusSource
Canonical Ubuntu Linux version 14.04version 16.04version 18.04version 18.10 Vulnerable NIST National Vulnerability Database
Debian Debian Linux version 9.0version 8.0 Vulnerable NIST National Vulnerability Database
Nodejs Node.js ≥ 10.0.0 and < 10.9.0≥ 8.0.0 and < 8.11.4< 6.14.4 Vulnerable NIST National Vulnerability Database
Openssl Openssl ≥ 1.0.2 and < 1.0.2q≥ 1.1.0 and < 1.1.0i Vulnerable NIST National Vulnerability Database
Oracle Api Gateway version 11.1.2.4.0 Vulnerable NIST National Vulnerability Database
Oracle Application Server version 1.0.1version 1.0.0version 0.9.8 Vulnerable NIST National Vulnerability Database
Oracle Enterprise Manager Base Platform version 13.3.0.0.0version 13.2.0.0.0version 12.1.0.5.0 Vulnerable NIST National Vulnerability Database
Oracle Enterprise Manager Ops Center version 12.3.3 Vulnerable NIST National Vulnerability Database
Oracle Mysql Enterprise Backup ≥ 3.12.4 and ≤ 4.1.2≤ 3.12.3 Vulnerable NIST National Vulnerability Database
Oracle Peoplesoft Enterprise Peopletools version 8.55version 8.56version 8.57 Vulnerable NIST National Vulnerability Database
Oracle Primavera P6 Enterprise Project Portfolio Management ≥ 17.7 and ≤ 17.12version 8.4version 15.1version 15.2version 16.1version 16.2version 18.8 Vulnerable NIST National Vulnerability Database
Oracle Tuxedo version 12.1.1.0.0 Vulnerable NIST National Vulnerability Database
Oracle Vm Virtualbox < 6.0.0 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Desktop version 7.0 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server version 7.0version 7.6 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server Aus version 7.6 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server Eus version 7.6 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server Tus version 7.6 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Workstation version 7.0 Vulnerable NIST National Vulnerability Database
Tenable Nessus < 8.1.1 Vulnerable NIST National Vulnerability Database

Attack characteristics

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

Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Every base score collected

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

ScoreVersionSeverityExpl.ImpactScored by
4.7 CVSS 3.1 Medium 1.0 3.6 nvd@nist.gov via NIST National Vulnerability Database
1.9 CVSS 2.0 Low 3.4 2.9 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-203 · Observable Discrepancy

Other CVEs with this weakness →

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Exploit-DB

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 3.42%

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.
endpoint telemetry (EDR)application logsauthentication logs

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
  • 2018
  • CVE published
    Nov 15, 2018 · certcc

Source activity

Repeated readings are counted rather than listed.

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

References

28 on the record

Elsewhere on this site

Canonical
every CVE for this vendor
Info disclosure
same class
CWE-203
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-103946 SQL Injection 2d
  • CVE-2026-84784 QUIC: Unbounded RETIRE_CONNECTION_ID Backlog 17d
  • CVE-2026-84783 Use-After-Free in X.509 Extension Cache Under Concurrent Use 17d
  • CVE-2026-84782 DTLS Retransmits Handshake Messages From a Stale Buffer Offset 17d
  • CVE-2026-77696 Timing Side-Channel in SM2 Signature Generation 17d
  • CVE-2026-75806 Unauthenticated and Undersized DTLS 1.2 AEAD Record Causes DoS 17d

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-2018-5407 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 3.42% 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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