Low Integrity

CVE-2026-25602 — Insufficient Verification of Data Authenticity in Mesalvo Meona Client

Insufficient Verification of Data Authenticity in the feedback function of Mesalvo MEONA (MEONA Client and MEONA Server). The MEONA Client transmits the recipient address of a feedback report to the MEONA Server, and the server sends the report to the transmitted address instead of the address configured on the server. The feedback function is available only in the MEONA administration area, which requires one of the administrative roles ADMINISTRATOR, SUPERADMINISTRATOR or TYPIST (catalogue editing), or the PHARMACIST role holding the PHARMACY_ADMINISTRATOR right, assigned explicitly by the operating hospital's administrators. Such a user who modifies the client request can cause the MEONA Server to send a message with content of the user's choosing, from the sender address configured on the server, to a recipient of the user's choosing, within the limits permitted by the operator's mail relay. The message can be used for social engineering because it appears to originate from an internal hospital system. Exploitation requires a MEONA account with one of the administrative roles named above and access to the operating hospital's internal network; MEONA is operated exclusively within closed hospital networks without exposure to the public Internet, and where a hospital permits remote access to that network at all, it is only through the hospital's own remote-access infrastructure (e.g. VPN) under the hospital's control. The message contains only the recipient, subject and text entered by the user; no data of other users or patients is disclosed. Mesalvo is not aware of any exploitation outside the reported security test. This issue affects MEONA Client and MEONA Server in versions 2024.10, 2025.04 (before 2025.04.24) and 2026.03 (before 2026.03.02). MEONA 2025.04.24 and 2026.03.02 (planned Q4 2026) enforce the configured recipient address on the server. Operators can restrict at their mail relay which recipients the MEONA sender address may reach.

Published May 20, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: ENISA

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 0.1% (30-day exploitation probability)+0

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

0.09%

ahead of 1% of scored CVEs · Oct 14, 2026

Affects

Mesalvo

Meona Client and 1 more

CVSS base

2.3

Low · 2 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

Partial

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 (Mesalvo Meona Client, Mesalvo Meona Server).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (integrity), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Mesalvo	Meona Client	version 2024.10≥ 2025.04 and < 2025.04.24≥ 2026.03 and < 2026.03.02	Vulnerable	CVE Program (cve.org) e CISA ADP
Mesalvo	Meona Server	version 2024.10≥ 2025.04 and < 2025.04.24≥ 2026.03 and < 2026.03.02	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

None

Integrity

Low

Availability

None

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
2.3	CVSS 3.1	Low	0.8	1.4	a6d3dc9e-0591-4a13-bce7-0f5b31ff6158 via NIST National Vulnerability Database
2.3	CVSS 3.1	Low	—	—	ENISA via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N (score shown at the top: a6d3dc9e-0591-4a13-bce7-0f5b31ff6158)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-345 · Insufficient Verification of Data Authenticity

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.09%

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.

endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · mesalvo/meona server, mesalvo/meona client
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 · 2.3
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Deferred
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
May 20, 2026 · ENISA

Source activity

Repeated readings are counted rather than listed.

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

References

1 on the record

mesalvo.com/en/vdp/advisories/msa-2026-005.pdf
vendor-advisory, NIST National Vulnerability Database

Elsewhere on this site

Mesalvo
every CVE for this vendor

Integrity
same class

CWE-345
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-0857 Use of a Password Hash With Insufficient Computational Effort in Mesalvo MEONA (MEONA… May 20, 2026
High CVE-2026-0856 Improper Access Control in Mesalvo Meona Client May 20, 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-2026-25602 is "Insufficient Verification of Data Authenticity in Mesalvo Meona Client", rated Low. It affects Meona Client (Mesalvo); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 2.3 describes technical severity. EPSS 0.09% 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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