CVE-2017-7901

A Predictable Value Range from Previous Values issue was discovered in Rockwell Automation Allen-Bradley MicroLogix 1100 programmable-logic controllers 1763-L16AWA, Series A and B, Version 16.00 and prior versions; 1763-L16BBB, Series A and B, Version 16.00 and prior versions; 1763-L16BWA, Series A and B, Version 16.00 and prior versions; and 1763-L16DWD, Series A and B, Version 16.00 and prior versions and Allen-Bradley MicroLogix 1400 programmable logic controllers 1766-L32AWA, Series A and B, Version 16.00 and prior versions; 1766-L32BWA, Series A and B, Version 16.00 and prior versions; 1766-L32BWAA, Series A and B, Version 16.00 and prior versions; 1766-L32BXB, Series A and B, Version 16.00 and prior versions; 1766-L32BXBA, Series A and B, Version 16.00 and prior versions; and 1766-L32AWAA, Series A and B, Version 16.00 and prior versions. Insufficiently random TCP initial sequence numbers are generated, which may allow an attacker to predict the numbers from previous values. This may allow an attacker to spoof or disrupt TCP connections, resulting in a denial of service for the target device.

Published: 2017-06-29 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-7901 is rated High Risk (71.9/100): CVSS High severity, with high exploitation likelihood (EPSS 6.62%, 93th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +6.54% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2017-7901

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.08% 6.62% +6.54%
2 2025-03-30 0.04% 0.08% +0.03%
3 2025-03-29 — 0.04% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-7901

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.6 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 4.7 [email protected]
9.0 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:C)
Complete availability impact.
 10.0 8.5 [email protected]

Weakness enumeration for CVE-2017-7901

Affected software / configurations for CVE-2017-7901

Vendor Product Version Raw CPE
rockwellautomation 1763-l16awa_series_a <= 16.000 cpe:2.3:a:rockwellautomation:1763-l16awa_series_a:*:*:*:*:*:*:*:*
rockwellautomation 1763-l16awa_series_b <= 16.000 cpe:2.3:a:rockwellautomation:1763-l16awa_series_b:*:*:*:*:*:*:*:*
rockwellautomation 1763-l16bbb_series_a <= 16.000 cpe:2.3:a:rockwellautomation:1763-l16bbb_series_a:*:*:*:*:*:*:*:*
rockwellautomation 1763-l16bbb_series_b <= 16.000 cpe:2.3:a:rockwellautomation:1763-l16bbb_series_b:*:*:*:*:*:*:*:*
rockwellautomation 1763-l16bwa_series_a <= 16.000 cpe:2.3:a:rockwellautomation:1763-l16bwa_series_a:*:*:*:*:*:*:*:*
rockwellautomation 1763-l16bwa_series_b <= 16.000 cpe:2.3:a:rockwellautomation:1763-l16bwa_series_b:*:*:*:*:*:*:*:*
rockwellautomation 1763-l16dwd_series_a <= 16.000 cpe:2.3:a:rockwellautomation:1763-l16dwd_series_a:*:*:*:*:*:*:*:*
rockwellautomation 1763-l16dwd_series_b <= 16.000 cpe:2.3:a:rockwellautomation:1763-l16dwd_series_b:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32awa_series_a <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32awa_series_a:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32awa_series_b <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32awa_series_b:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32awaa_series_a <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32awaa_series_a:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32awaa_series_b <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32awaa_series_b:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32bwa_series_a <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32bwa_series_a:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32bwa_series_b <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32bwa_series_b:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32bwaa_series_a <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32bwaa_series_a:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32bwaa_series_b <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32bwaa_series_b:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32bxb_series_a <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32bxb_series_a:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32bxb_series_b <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32bxb_series_b:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32bxba_series_a <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32bxba_series_a:*:*:*:*:*:*:*:*
rockwellautomation 1766-l32bxba_series_b <= 16.000 cpe:2.3:a:rockwellautomation:1766-l32bxba_series_b:*:*:*:*:*:*:*:*

References for CVE-2017-7901

cvelogic Threat Intelligence