What’s Vulnerable › Vulnerabilities

CVE-2015-3963

• Severity: medium (CVSS 5.8 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2015-08-04 · updated 2026-06-17
• Weakness: CWE-330

Description

Wind River VxWorks before 5.5.1, 6.5.x through 6.7.x before 6.7.1.1, 6.8.x before 6.8.3, 6.9.x before 6.9.4.4, and 7.x before 7 ipnet_coreip 1.2.2.0, as used on Schneider Electric SAGE RTU devices before J2 and other devices, does not properly generate TCP initial sequence number (ISN) values, which makes it easier for remote attackers to spoof TCP sessions by predicting an ISN value.

Affected products

• Windriver Vxworks: from 6.5 through 6.6; from 6.7 before 6.7.1.1; from 6.8 before 6.8.3; from 6.9 before 6.9.4.4; 6.6.3, 6.6.4, 6.6.4.1, 7.0 — fixed in 6.7.1.1, 6.8.3, 6.9.4.4

How to fix

Upgrade to a fixed version: Windriver Vxworks 6.7.1.1, 6.8.3, 6.9.4.4. Check the vendor advisory for mitigations.

References

• http://www.schneider-electric.com/ww/en/download/document/SEVD-2015-162-01
• http://www.securityfocus.com/bid/75302
• http://www.securitytracker.com/id/1032730
• http://www.securitytracker.com/id/1033181
• https://ics-cert.us-cert.gov/advisories/ICSA-15-169-01
• https://ics-cert.us-cert.gov/advisories/ICSA-15-169-01A
• https://security.netapp.com/advisory/ntap-20160324-0001/
• http://www.schneider-electric.com/ww/en/download/document/SEVD-2015-162-01
• http://www.securityfocus.com/bid/75302
• http://www.securitytracker.com/id/1032730
• http://www.securitytracker.com/id/1033181
• https://ics-cert.us-cert.gov/advisories/ICSA-15-169-01

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