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Successful exploitation of this vulnerability could crash the device being accessed; a buffer overflow condition may allow remote code execution.
The following versions of Savannah lwIP SMTP client are affected:
lwIP SMTP client does not check the size of inputs, potentially allowing a buffer overflow.
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Product Status: known_affected
Mitigation
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)
Relevant CWE: CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
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This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
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.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
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.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
Summary
Successful exploitation of this vulnerability could crash the device being accessed; a buffer overflow condition may allow remote code execution.
The following versions of Savannah lwIP SMTP client are affected:
- lwIP SMTP client 2.2.1 (CVE-2026-15340)
| CVSS | Vendor | Equipment |
|---|---|---|
| v3 9.8 | Savannah | lwIP SMTP client |
| 1 Vulnerability |
|---|
| Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') |
Background
- Critical Infrastructure Sectors: Energy, Water and Wastewater Systems
- Countries/Areas Deployed: Worldwide
- Company Headquarters Location: Sweden
Vulnerabilities
CVE-2026-15340lwIP SMTP client does not check the size of inputs, potentially allowing a buffer overflow.
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1 Affected Product
Savannah lwIP SMTP client: 2.2.1
Product Status: known_affected
Remediations
Mitigation
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)
Additional Metrics
Relevant CWE: CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
| CVSS Version | Base Score | Base Severity | Vector String |
|---|---|---|---|
| 3.1 | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 4.0 | 9.3 | CRITICAL | 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 |
View CVE Details
Acknowledgments
- xchglabs reported this vulnerability directly to Savannah and then disclosed once the fix was released
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).
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.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
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.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
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.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
Revision History
- Initial Release Date: 2026-10-06
| Date | Revision | Summary |
|---|---|---|
| 2026-10-06 | 1 | Initial Publication |