Medium

CVE-2026-0857 — Use of a Password Hash With Insufficient Computational Effort in Mesalvo MEONA (MEONA…

Use of a Password Hash With Insufficient Computational Effort in Mesalvo MEONA (MEONA Server and MEONA Client) for user accounts whose password was last set under a version before MEONA 2024.10. MEONA versions before 2024.10 protected stored passwords with SHA-1 (versions from October 2015) or stored them without protection (earlier versions). Since MEONA 2024.10 (June 2024) Argon2 is the default method and every password that is set or changed is stored with Argon2; passwords last set under an earlier version keep the earlier method until they are changed. An administrator could in addition select the storage method per account. A MEONA super administrator can read the stored value of such accounts in the user administration of the MEONA Client or export it through administrative database functions. Only accounts managed locally in MEONA are affected; accounts authenticated through the operating hospital's directory service (Active Directory / Entra ID) have no password stored in MEONA. In typical installations end users authenticate through the directory service and local accounts are limited to emergency and technical accounts. Exploitation requires super administrator permissions in MEONA (or direct access to the MEONA database) from within the operating hospital's 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. Installations in which every password has been set or changed under MEONA 2024.10 or later are not affected. Mesalvo is not aware of any exploitation outside the reported security test. This issue affects MEONA Server and MEONA Client in versions 2024.10, 2025.04 and 2026.03 (for accounts with passwords last set under earlier versions). MEONA 2025.04.24 and 2026.03.02 (planned Q4 2026) remove the legacy storage methods, require every affected account to set a new Argon2-protected password at next logon, and no longer display stored credential values in the user administration. See Mesalvo Security Advisory MSA-2026-002.

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
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

0.1%

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

Affects

Mesalvo

Meona Client and 1 more

CVSS base

4.4

Medium · 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, 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

High

Integrity

None

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
4.4	CVSS 3.1	Medium	0.8	3.6	a6d3dc9e-0591-4a13-bce7-0f5b31ff6158 via NIST National Vulnerability Database
4.4	CVSS 3.1	Medium	—	—	ENISA via CVE Program (cve.org) e CISA ADP

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

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-916

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.10%

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 client, mesalvo/meona server
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 · 4.4
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-2026-002.pdf
vendor-advisory, NIST National Vulnerability Database

Elsewhere on this site

Mesalvo
every CVE for this vendor

CWE-916
other pages naming this weakness

Related CVEs (same products)

Low CVE-2026-25602 Insufficient Verification of Data Authenticity in Mesalvo Meona Server 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-2026-0857 is "Use of a Password Hash With Insufficient Computational Effort in Mesalvo MEONA (MEONA…", rated Medium. It affects Meona Client (Mesalvo); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.4 describes technical severity. EPSS 0.10% 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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