CVE-2026-54586

Package tampering via unchecked cleartext fetch URLs

Published Sep 17, 2026 · Updated Sep 21, 2026

Cleartext transport in MidnightBSD Mport before 2.7.8 allows attackers to tamper with package fetch traffic from a network position. The mport_fetch_index(), mport_fetch_bootstrap_index(), and mport_fetch_bundle() paths accepted repository and mirror URLs without requiring the https:// scheme. Exposure requires a configured or mirror-supplied cleartext URL and traffic interception, enabling altered package selection or package contents.

CVSS severity6.0
Medium
EPSS probability0.15%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cleartext transport in MidnightBSD Mport before 2.7.8 allows attackers to tamper with package fetch traffic from a network position. The mport_fetch_index(), mport_fetch_bootstrap_index(), and mport_fetch_bundle() paths accepted repository and mirror URLs without requiring the https:// scheme. Exposure requires a configured or mirror-supplied cleartext URL and traffic interception, enabling altered package selection or package contents.

The record

CVE
CVE-2026-54586
Published
Sep 17, 2026
Updated
Sep 21, 2026
Vendor
MidnightBSD
Product
Mport
Classifications
CWE-319, CWE-345, T1557
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.7.8

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

MidnightBSD · Mportversion=< 2.7.8

Published CVSS scores

6.0GitHub Security AdvisoryCVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-319Cleartext Transmission of Sensitive Information
CWE-345Insufficient Verification of Data Authenticity
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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