CVE-2026-43798: A single crafted SSH message gives an unauthenticated network attacker an out-of-bounds stack write of attacke

Q: How do I fix CVE-2026-43798?

swiftnio ssh: upgrade to 0.14.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-43798 being exploited?

CVE-2026-43798 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-43798 affect?

CVE-2026-43798 affects swiftnio ssh. Severity is critical (CVSS 9.8). 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 v

Q: How urgent is CVE-2026-43798?

Priority 49/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-43798 is a critical-severity flaw (CVSS 9.8) affecting swiftnio ssh. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-121
Published	2026-08-20
Last modified	2026-10-18

Publisher (CNA): Apple Inc. · Vendor: apple

Last updated 2026-10-18 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-20 21:17 UTCPublished CVE record published
2026-10-18 20:10 UTCUpdated Record last modified

apple swiftnio ssh UPGRADE

Affected: < 0.14.1

Fixed in: 0.14.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy swiftnio-ssh || rpm -q swiftnio-ssh || swiftnio-ssh --version

2. UPGRADE to 0.14.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade swiftnio-ssh

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade swiftnio-ssh

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-43798?

swiftnio ssh: upgrade to 0.14.1. Exact commands for each OS are on this page.

Is CVE-2026-43798 being exploited?

CVE-2026-43798 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-43798 affect?

CVE-2026-43798 affects swiftnio ssh. Severity is critical (CVSS 9.8). 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 v

How urgent is CVE-2026-43798?

Priority 49/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

Swift vulnerabilities

References

← Back to latest CVEs