Medium
nagios4 — security advisory
Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to reflected cross-site scripting in cmd.cgi via the NagFormId parameter. An unauthenticated remote attacker can craft a malicious link that, when followed by an authenticated user, executes arbitrary JavaScript in the victim's browser.
- Products
- nagios4
- Affected versions
- 4.3.4-3, 4.3.4-3ubuntu0.1, 4.4.6-4, 4.4.6-4.1ubuntu1, 4.4.6-4.1ubuntu2, 4.4.6-4ubuntu0.22.04.1, 4.4.6-4ubuntu0.24.04.1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-48550
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:07 UTC · Revision 1
Source evidence
Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to reflected cross-site scripting in cmd.cgi via the NagFormId parameter. An unauthenticated remote attacker can craft a malicious link that, when followed by an authenticated user, executes arbitrary JavaScript in the victim's browser.
osv:UBUNTU-CVE-2026-48550
nagios4
Fixed versions: Not specified
nagios4
Fixed versions: Not specified
nagios4
Fixed versions: Not specified
nagios4
Fixed versions: Not specified
nagios4
Fixed versions: Not specified
Complete source record
{
"id": "86e3ed50693778d0d7e1e0ece13f5f2639c4644e6bec2a2b64e0dbfa591b645f",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-48550",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-48550",
"summary": "Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to reflected cross-site scripting in cmd.cgi via the NagFormId parameter. An unauthenticated remote attacker can craft a malicious link that, when followed by an authenticated user, executes arbitrary JavaScript in the victim's browser.",
"evidence": "osv:UBUNTU-CVE-2026-48550",
"products": [
{
"name": {
"value": "nagios4",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "4.3.4-3",
"evidence": "/affected/0/versions"
},
{
"value": "4.3.4-3ubuntu0.1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
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"evidence": "/affected/1/package/name"
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"affected_versions": [
{
"value": "4.4.6-4",
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},
{
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"evidence": "/affected/1/versions"
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{
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{
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"evidence": "/affected/3/package/name"
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"affected_versions": [
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},
{
"name": {
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"affected_versions": [
{
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"evidence": "/affected/4/versions"
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{
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"evidence": "/affected/4/versions"
}
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],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2026-48550",
"aliases": [
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],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
},
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nagios4",
"purl": "pkg:deb/ubuntu/nagios4?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"4.3.4-3",
"4.3.4-3ubuntu0.1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48550.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nagios4",
"binary_version": "4.3.4-3ubuntu0.1"
},
{
"binary_name": "nagios4-cgi",
"binary_version": "4.3.4-3ubuntu0.1"
},
{
"binary_name": "nagios4-common",
"binary_version": "4.3.4-3ubuntu0.1"
},
{
"binary_name": "nagios4-core",
"binary_version": "4.3.4-3ubuntu0.1"
}
]
}
},
{
"ranges": [
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"package": {
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"purl": "pkg:deb/ubuntu/nagios4?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
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},
"ecosystem_specific": {
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"binary_version": "4.4.6-4ubuntu0.22.04.1"
},
{
"binary_name": "nagios4-cgi",
"binary_version": "4.4.6-4ubuntu0.22.04.1"
},
{
"binary_name": "nagios4-common",
"binary_version": "4.4.6-4ubuntu0.22.04.1"
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{
"binary_name": "nagios4-core",
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{
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"package": {
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"purl": "pkg:deb/ubuntu/nagios4?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"4.4.6-4",
"4.4.6-4ubuntu0.24.04.1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48550.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nagios4",
"binary_version": "4.4.6-4ubuntu0.24.04.1"
},
{
"binary_name": "nagios4-cgi",
"binary_version": "4.4.6-4ubuntu0.24.04.1"
},
{
"binary_name": "nagios4-common",
"binary_version": "4.4.6-4ubuntu0.24.04.1"
},
{
"binary_name": "nagios4-core",
"binary_version": "4.4.6-4ubuntu0.24.04.1"
}
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},
{
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"purl": "pkg:deb/ubuntu/nagios4?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"4.4.6-4.1ubuntu2"
],
"database_specific": {
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},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nagios4",
"binary_version": "4.4.6-4.1ubuntu2"
},
{
"binary_name": "nagios4-cgi",
"binary_version": "4.4.6-4.1ubuntu2"
},
{
"binary_name": "nagios4-common",
"binary_version": "4.4.6-4.1ubuntu2"
},
{
"binary_name": "nagios4-core",
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}
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},
{
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"package": {
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"purl": "pkg:deb/ubuntu/nagios4?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"4.4.6-4.1ubuntu1",
"4.4.6-4.1ubuntu2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48550.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nagios4",
"binary_version": "4.4.6-4.1ubuntu2"
},
{
"binary_name": "nagios4-cgi",
"binary_version": "4.4.6-4.1ubuntu2"
},
{
"binary_name": "nagios4-common",
"binary_version": "4.4.6-4.1ubuntu2"
},
{
"binary_name": "nagios4-core",
"binary_version": "4.4.6-4.1ubuntu2"
}
]
}
}
],
"modified": "2026-10-17T13:00:22.903134742Z",
"provider": "osv",
"upstream": [
"CVE-2026-48550"
],
"references": [
"https://ubuntu.com/security/CVE-2026-48550",
"https://www.cve.org/CVERecord?id=CVE-2026-48550",
"https://github.com/NagiosEnterprises/nagioscore/blob/master/Changelog",
"https://www.nagios.com/security-disclosures/nagios-core/",
"https://www.vulncheck.com/advisories/nagios-core-xi-cmd-cgi-reflected-xss-via-nagformid-parameter"
]
},
"related_cves": [
{
"value": "CVE-2026-48550",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 360457,
"published_at": "2026-08-12T17:17:00+00:00"
}