Medium Access control

CVE-2025-34288 — Nagios XI Privilege Escalation via Writable PHP Include Executed with Sudo

Nagios XI versions prior to 2026R1.1 are vulnerable to local privilege escalation due to an unsafe interaction between sudo permissions and application file permissions. A user‑accessible maintenance script may be executed as root via sudo and includes an application file that is writable by a lower‑privileged user. A local attacker with access to the application account can modify this file to introduce malicious code, which is then executed with elevated privileges when the script is run. Successful exploitation results in arbitrary code execution as the root user.

Published Dec 16, 2025 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: VulnCheck

Low

Who exploits it and how urgent it is

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

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 1.9% (30-day exploitation probability)+12
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

1.85%

ahead of 79% of scored CVEs · Oct 15, 2026

Affects

Nagios

Nagios Xi and 1 more

CVSS base

6.7

Medium · 3 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

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

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

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

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.

Identify exposed assets running the affected vendor/product/version combinations (Nagios Nagios Xi, Nagios Enterprises Nagios XI).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Nagios	Nagios Xi	≤ 2024version 2026-r1version 2026-r1.0.1	Vulnerable	NIST National Vulnerability Database
Nagios Enterprises	Nagios XI	< 2026R1.1	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

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

Attack vector

Local

Attack complexity

Low

Privileges required

High

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

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

Score	Version	Severity	Expl.	Impact	Scored by
8.6	CVSS 4.0	High	—	—	disclosure@vulncheck.com via NIST National Vulnerability Database
8.6	CVSS 4.0	High	—	—	VulnCheck via CVE Program (cve.org) e CISA ADP
6.7	CVSS 3.1	Medium	0.8	5.9	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-732 · Incorrect Permission Assignment for Critical Resource

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 1.85%

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.
Audit administrative actions and access to resources outside each user’s normal pattern.

endpoint telemetry (EDR)authentication logsapplication logs

Timeline

What happened to this CVE, newest first.

2026
Affected products added · nagios enterprises/nagios xi
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 6.7
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
2025
CVE published
Dec 16, 2025 · VulnCheck

Source activity

Repeated readings are counted rather than listed.

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

References

2 on the record

www.nagios.com/changelog/nagios-xi/2026r1-1/
Release Notes, release-notes, patch, NIST National Vulnerability Database
www.vulncheck.com/advisories/nagios-xi-privilege-escalation-via-writable-php-include-ex
Third Party Advisory, third-party-advisory, NIST National Vulnerability Database

Elsewhere on this site

Nagios
every CVE for this vendor

Access control
same class

CWE-732
other pages naming this weakness

Related CVEs (same products)

Low CVE-2023-24034 Open Redirect in Nagios Nagios Xi Sep 14, 2026
Low CVE-2023-24035 An issue was discovered in Nagios XI before 5.9.3. The is_insecure_login_authenticated… Sep 14, 2026
Medium CVE-2026-48549 Nagios Core / XI CSRF via cmd.cgi Double-Submit Cookie Aug 26, 2026
Medium CVE-2026-48550 Nagios Core / XI cmd.cgi Reflected XSS via NagFormId Parameter Aug 12, 2026
High CVE-2026-48551 Nagios Core / XI CSRF Protection Bypass via Double-Submit Cookie Aug 12, 2026
Medium CVE-2026-48552 Nagios Core / XI DOM-based XSS via jsonquery.js Aug 12, 2026

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 fixed version, patch or mitigation documented.
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-2025-34288 is "Nagios XI Privilege Escalation via Writable PHP Include Executed with Sudo", rated Medium. It affects Nagios Xi (Nagios); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.7 describes technical severity. EPSS 1.85% 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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