SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-43798

A single crafted SSH message gives an unauthenticated network attacker an out-of-bounds stack write of attacker-controlled length and content against any application built on swift-nio-ssh.

CRITICAL 9.8EPSS 0.34%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.34%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

A single crafted SSH message gives an unauthenticated network attacker an out-of-bounds stack write of attacker-controlled length and content against any application built on swift-nio-ssh. This vulnerability is addressed in swift-nio-ssh version 0.14.1.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
0.34% probability · 27th percentile
CISA KEV
Not listed
Weakness
CWE-121
Affected
apple/swiftnio ssh
Source
product-security@apple.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.