ICSA-26-279-02
Vulnerability from csaf_cisa - Published: 2026-10-06 06:00 - Updated: 2026-10-06 06:00Summary
Savannah lwIP SMTP client
Notes
Legal Notice and Terms of Use: This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).
Advisory Summary: Successful exploitation of this vulnerability could crash the device being accessed; a buffer overflow condition may allow remote code execution.
Critical infrastructure sectors: Energy, Water and Wastewater Systems
Countries/areas deployed: Worldwide
Company headquarters location: Sweden
Recommended Practices: CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet. Locate control system networks and remote devices behind firewalls and isolating them from business networks. When remote access is required, use more secure methods, such as virtual private networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
Recommended Practices: CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
Recommended Practices: CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
Recommended Practices: CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
Recommended Practices: Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.
Recommended Practices: Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
9.8 (Critical)
Affected products
Known affected
1 product
| Product | Identifier | Version | Remediation |
|---|---|---|---|
|
Savannah lwIP SMTP client: 2.2.1
Savannah / lwIP SMTP client
|
2.2.1 |
Mitigation
|
References
15 references
{
"document": {
"acknowledgments": [
{
"organization": "xchglabs",
"summary": "reported this vulnerability directly to Savannah and then disclosed once the fix was released"
}
],
"category": "csaf_security_advisory",
"csaf_version": "2.0",
"distribution": {
"text": "Disclosure is not limited",
"tlp": {
"label": "WHITE",
"url": "https://www.cisa.gov/news-events/news/traffic-light-protocol-tlp-definitions-and-usage"
}
},
"lang": "en-US",
"notes": [
{
"category": "legal_disclaimer",
"text": "This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy \u0026 Use policy (https://www.cisa.gov/privacy-policy).",
"title": "Legal Notice and Terms of Use"
},
{
"category": "summary",
"text": "Successful exploitation of this vulnerability could crash the device being accessed; a buffer overflow condition may allow remote code execution.",
"title": "Advisory Summary"
},
{
"category": "other",
"text": "Energy, Water and Wastewater Systems",
"title": "Critical infrastructure sectors"
},
{
"category": "other",
"text": "Worldwide",
"title": "Countries/areas deployed"
},
{
"category": "other",
"text": "Sweden",
"title": "Company headquarters location"
},
{
"category": "general",
"text": "CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet. Locate control system networks and remote devices behind firewalls and isolating them from business networks. When remote access is required, use more secure methods, such as virtual private networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.",
"title": "Recommended Practices"
},
{
"category": "general",
"text": "CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.",
"title": "Recommended Practices"
},
{
"category": "general",
"text": "CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.",
"title": "Recommended Practices"
},
{
"category": "general",
"text": "CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.",
"title": "Recommended Practices"
},
{
"category": "general",
"text": "Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.",
"title": "Recommended Practices"
},
{
"category": "general",
"text": "Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.",
"title": "Recommended Practices"
}
],
"publisher": {
"category": "coordinator",
"contact_details": "central@cisa.dhs.gov",
"name": "CISA",
"namespace": "https://www.cisa.gov/"
},
"references": [
{
"category": "self",
"summary": "ICS Advisory ICSA-26-279-02 JSON",
"url": "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2026/icsa-26-279-02.json"
},
{
"category": "self",
"summary": "ICSA Advisory ICSA-26-279-02 - Web Version",
"url": "https://www.cisa.gov/news-events/ics-advisories/icsa-26-279-02"
},
{
"category": "external",
"summary": "Recommended Practices",
"url": "https://www.cisa.gov/uscert/ics/alerts/ICS-ALERT-10-301-01"
},
{
"category": "external",
"summary": "Recommended Practices",
"url": "https://www.cisa.gov/resources-tools/resources/ics-recommended-practices"
},
{
"category": "external",
"summary": "Recommended Practices",
"url": "https://www.cisa.gov/sites/default/files/publications/Cybersecurity_Best_Practices_for_Industrial_Control_Systems.pdf"
},
{
"category": "external",
"summary": "Recommended Practices",
"url": "https://www.cisa.gov/topics/industrial-control-systems"
},
{
"category": "external",
"summary": "Recommended Practices",
"url": "https://www.cisa.gov/news-events/ics-alerts/ics-alert-10-301-01"
},
{
"category": "external",
"summary": "Recommended Practices",
"url": "https://www.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf"
},
{
"category": "external",
"summary": "Recommended Practices",
"url": "https://www.cisa.gov/news-events/news/targeted-cyber-intrusion-detection-and-mitigation-strategies-update-b"
},
{
"category": "external",
"summary": "Recommended Practices",
"url": "https://www.cisa.gov/secure-our-world/teach-employees-avoid-phishing"
},
{
"category": "external",
"summary": "Recommended Practices",
"url": "https://www.cisa.gov/news-events/news/avoiding-social-engineering-and-phishing-attacks"
}
],
"title": "Savannah lwIP SMTP client",
"tracking": {
"current_release_date": "2026-10-06T06:00:00.000000Z",
"generator": {
"date": "2026-10-05T21:13:37.355581Z",
"engine": {
"name": "CISA CSAF Generator",
"version": "1.0.0"
}
},
"id": "ICSA-26-279-02",
"initial_release_date": "2026-10-06T06:00:00.000000Z",
"revision_history": [
{
"date": "2026-10-06T06:00:00.000000Z",
"legacy_version": "Initial",
"number": "1",
"summary": "Initial Publication"
}
],
"status": "final",
"version": "1"
}
},
"product_tree": {
"branches": [
{
"branches": [
{
"branches": [
{
"category": "product_version",
"name": "2.2.1",
"product": {
"name": "Savannah lwIP SMTP client: 2.2.1",
"product_id": "CSAFPID-0001"
}
}
],
"category": "product_name",
"name": "lwIP SMTP client"
}
],
"category": "vendor",
"name": "Savannah"
}
]
},
"vulnerabilities": [
{
"cve": "CVE-2026-15340",
"cwe": {
"id": "CWE-120",
"name": "Buffer Copy without Checking Size of Input (\u0027Classic Buffer Overflow\u0027)"
},
"notes": [
{
"category": "summary",
"text": "lwIP SMTP client does not check the size of inputs, potentially allowing a buffer overflow.",
"title": "Vulnerability Summary"
},
{
"category": "details",
"text": "SSVCv2/E:P/A:Y/2026-10-05T06:00:00.000000Z",
"title": "SSVC"
}
],
"product_status": {
"known_affected": [
"CSAFPID-0001"
]
},
"references": [
{
"category": "external",
"summary": "cwe.mitre.org",
"url": "https://cwe.mitre.org/data/definitions/120.html"
},
{
"category": "external",
"summary": "www.cve.org",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-15340"
},
{
"category": "external",
"summary": "www.first.org",
"url": "https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
},
{
"category": "external",
"summary": "www.first.org",
"url": "https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
}
],
"remediations": [
{
"category": "mitigation",
"details": "xchglabs reports that the vulnerability was fixed and released in the following patch: patch_125_smtp_txbuf.diff . This is available as available as git commit (614420f82c8729d070e01464c0dddb3c9525c772)",
"product_ids": [
"CSAFPID-0001"
]
}
],
"scores": [
{
"cvss_v3": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"products": [
"CSAFPID-0001"
]
}
]
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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