CVE-2025-26466

Openssh vulnerability

CVSS

5.9

EPSS

38.5%

EPSS pct

98th

Exploited

No known

A flaw was found in the OpenSSH package. For each ping packet the SSH server receives, a pong packet is allocated in a memory buffer and stored in a queue of packages. It is only freed when the server/client key exchange has finished. A malicious client may keep sending such packages, leading to an uncontrolled increase in memory consumption on the server side. Consequently, the server may become unavailable, resulting in a denial of service attack.

Affected vendor

Openbsd

Affected product

Openssh

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness type (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

Published

2025-02-28

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, high attack complexity, requiring no privileges, no user interaction. Successful exploitation leads to high impact to availability.

Its EPSS score of 38.5% reflects a moderate probability of exploitation activity in the wild over the next 30 days, placing it above 98% of all scored CVEs.

Check your external exposure to CVE-2025-26466

Confirm whether Openbsd Openssh is running on any internet-facing host or subdomain.
Match discovered service fingerprints against the version affected by CVE-2025-26466.
Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2025-26466

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2025-26466 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

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