UBUNTU-CVE-2026-48686

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Source
https://ubuntu.com/security/CVE-2026-48686
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48686.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-48686
Upstream
  • CVE-2026-48686
Downstream
Related
Published
2026-05-26T16:16:00Z
Modified
2026-06-16T05:00:07.069967749Z
Severity
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

FastNetMon Community Edition through 1.2.9 contains a stack-based buffer overflow in the BGP NLRI (Network Layer Reachability Information) decoder. The function decodebgpsubnetencodingipv4raw() in src/bgpprotocol.cpp reads prefixbitlength directly from the BGP packet (line 99) without validating it is <= 32 for IPv4 prefixes. This value is passed to howmuchbytesweneedforstoringcertainsubnetmask() which computes ceil(prefixbitlength / 8), returning up to 32 bytes for a prefixbitlength of 255. The result is used as the length argument to memcpy() (line 106), which copies into a 4-byte uint32t stack variable (prefixipv4). This causes a stack buffer overflow of up to 28 bytes, which can be exploited for arbitrary code execution. Additionally, the unvalidated prefixbitlength is passed to convertcidrtobinarynetmasklocalfunctioncopy() (line 111), where a shift of (32 - cidr) with cidr > 32 causes undefined behavior.

References

Affected packages

Ubuntu:Pro:24.04:LTS / fastnetmon

Package

Name
fastnetmon
Purl
pkg:deb/ubuntu/fastnetmon?arch=source&distro=esm-apps%2Fnoble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.2.6-1ubuntu0.1~esm1

Affected versions

1.*
1.2.5-1
1.2.6-1
1.2.6-1build1
1.2.6-1build2
1.2.6-1build3
1.2.6-1build4

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1.2.6-1ubuntu0.1~esm1",
            "binary_name": "fastnetmon"
        }
    ],
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48686.json"

Ubuntu:25.10 / fastnetmon

Package

Name
fastnetmon
Purl
pkg:deb/ubuntu/fastnetmon?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

1.*
1.2.8-1build1
1.2.8-1build2
1.2.8+git20250911-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1.2.8+git20250911-1",
            "binary_name": "fastnetmon"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48686.json"

Ubuntu:Pro:26.04:LTS / fastnetmon

Package

Name
fastnetmon
Purl
pkg:deb/ubuntu/fastnetmon?arch=source&distro=esm-apps%2Fresolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.2.8+git20250911-2ubuntu0.1~esm1

Affected versions

1.*
1.2.8+git20250911-1
1.2.8+git20250911-1build1
1.2.8+git20250911-1build2
1.2.8+git20250911-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "1.2.8+git20250911-2ubuntu0.1~esm1",
            "binary_name": "fastnetmon"
        }
    ],
    "availability": "Available with Ubuntu Pro: https://ubuntu.com/pro"
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48686.json"