Security readout for executives and security teams
Plain-English summary
Applications using Apple’s swift-nio-ssh can be compromised by a remote, unauthenticated attacker sending one crafted SSH message. The flaw can corrupt stack memory with attacker-controlled content, potentially affecting confidentiality, integrity, and availability. Version 0.14.1 addresses the vulnerability.
Executive priority
Treat as an immediate remediation priority for attacker-reachable SSH services. Identify affected applications quickly, restrict exposure, and upgrade to 0.14.1 or later. Broader urgency depends on whether swift-nio-ssh is actually present and network-accessible.
Technical view
CVE-2026-43798 is a CWE-121 stack-based buffer overflow in swift-nio-ssh. A single crafted SSH message can cause an out-of-bounds stack write with attacker-controlled length and content. CVSS 3.1 rates it 9.8: network-accessible, low complexity, no privileges, and no user interaction.
Likely exposure
Exposure is likely where an application built on a vulnerable swift-nio-ssh release accepts SSH traffic from untrusted networks. The supplied evidence does not identify specific downstream applications, deployment defaults, or a complete affected-version range.
Exploitation context
The technical conditions indicate a remotely reachable, unauthenticated attack surface requiring one crafted message. However, the source bundle marks KEV false and provides no evidence of active exploitation or publicly available exploit tooling.
Researcher notes
The key primitive is an attacker-controlled out-of-bounds stack write triggered before authentication by one SSH message. This supports severe impact potential, but the supplied sources do not establish reliable code execution, affected platforms, exploit availability, or the complete vulnerable-version range.
Mitigation direction
- Upgrade swift-nio-ssh to version 0.14.1 or later.
- Prioritize internet-facing or otherwise untrusted-network SSH services.
- Restrict SSH reachability until affected deployments are upgraded.
- Check the Apple advisory for any additional vendor guidance.
Validation and detection
- Inspect dependency manifests, lockfiles, SBOMs, and deployed artifacts for swift-nio-ssh versions.
- Confirm production applications are rebuilt and deployed with version 0.14.1 or later.
- Inventory services accepting SSH traffic and map them to the dependency findings.
- Verify network controls limit SSH access to explicitly trusted sources.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-121: Exact CWE lookup
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Open ATT&CK lookupCVE-2026-43798 mapping review
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Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/apple/swift-nio-ssh/security/advisories/GHSA-998x-vgvp-xwpcCVE reference, apple
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Stack-based Buffer Overflow
Stack-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.