CVE-2017-7901

highpriority · track · 37OT risk · elevatedEPSS 0.090 · 95 %ileEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

9.05% (95th) EPSS

CVSS 9 · high

Is it mine?

41 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · cisa_csaf_ot

EPSS · scored 2026-10-27

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.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

No vendor fix yet; a mitigation is available.

Mitigation1763-L16AWA Series A and Bcisa_csaf_ot
Rockwell Automation has released a new firmware version for the Allen-Bradley MicroLogix 1400 Series B controllers, FRN 21.00, to address the identified vulnerabilities. Rockwell Automation encourages users to apply the latest firmware versions that address the identified vulnerabilities.
Mitigation1763-L16BBB Series A and Bcisa_csaf_ot
Rockwell Automation has released a new firmware version for the Allen-Bradley MicroLogix 1400 Series B controllers, FRN 21.00, to address the identified vulnerabilities. Rockwell Automation encourages users to apply the latest firmware versions that address the identified vulnerabilities.
Mitigation1763-L16BWA Series A and Bcisa_csaf_ot
Rockwell Automation has released a new firmware version for the Allen-Bradley MicroLogix 1400 Series B controllers, FRN 21.00, to address the identified vulnerabilities. Rockwell Automation encourages users to apply the latest firmware versions that address the identified vulnerabilities.
Mitigation1763-L16DWD Series A and Bcisa_csaf_ot
Rockwell Automation has released a new firmware version for the Allen-Bradley MicroLogix 1400 Series B controllers, FRN 21.00, to address the identified vulnerabilities. Rockwell Automation encourages users to apply the latest firmware versions that address the identified vulnerabilities.
Mitigation1766-L32AWA Series A and Bcisa_csaf_ot
Rockwell Automation has released a new firmware version for the Allen-Bradley MicroLogix 1400 Series B controllers, FRN 21.00, to address the identified vulnerabilities. Rockwell Automation encourages users to apply the latest firmware versions that address the identified vulnerabilities.
Mitigation1766-L32AWAA Series A and Bcisa_csaf_ot
Rockwell Automation has released a new firmware version for the Allen-Bradley MicroLogix 1400 Series B controllers, FRN 21.00, to address the identified vulnerabilities. Rockwell Automation encourages users to apply the latest firmware versions that address the identified vulnerabilities.
Mitigation1766-L32BWA Series A and Bcisa_csaf_ot
Rockwell Automation has released a new firmware version for the Allen-Bradley MicroLogix 1400 Series B controllers, FRN 21.00, to address the identified vulnerabilities. Rockwell Automation encourages users to apply the latest firmware versions that address the identified vulnerabilities.
Mitigation1766-L32BWAA Series A and Bcisa_csaf_ot
Rockwell Automation has released a new firmware version for the Allen-Bradley MicroLogix 1400 Series B controllers, FRN 21.00, to address the identified vulnerabilities. Rockwell Automation encourages users to apply the latest firmware versions that address the identified vulnerabilities.
Mitigation1766-L32BXB Series A and Bcisa_csaf_ot
Rockwell Automation has released a new firmware version for the Allen-Bradley MicroLogix 1400 Series B controllers, FRN 21.00, to address the identified vulnerabilities. Rockwell Automation encourages users to apply the latest firmware versions that address the identified vulnerabilities.
Mitigation1766-L32BXBA Series A and Bcisa_csaf_ot
Rockwell Automation has released a new firmware version for the Allen-Bradley MicroLogix 1400 Series B controllers, FRN 21.00, to address the identified vulnerabilities. Rockwell Automation encourages users to apply the latest firmware versions that address the identified vulnerabilities.

cvss

Technical severity, 0–10. One row per scoring source.

9.0

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.4–9

v2.09highAV:N/AC:L/Au:N/C:P/I:P/A:Cprimary · NVD / NIST USexploitability 10 · impact 8.5

v3.08.6highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 4.7

v3.05.4mediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:Lsecondary · CISA US

v3.07.9highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-330USprimaryCWE-343USCWE-343US

affected products (41)

Products and version ranges known to be affected.

showing 20 of 41

advisories (1)

Vendor and ecosystem advisories describing this.

ICSA-17-115-04Rockwell Automation Allen-Bradley MicroLogix 1100 and 14002017-04-25icsa · cisa_csaf_otUS
ATTENTION: Remotely exploitable/low skill level to exploit.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cisa_csaf_ot NVD CVE.org MITRE

published 2017-06-30modified 2026-06-17

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references (7)

External citations — patches, advisories, analysis.

http://www.rockwellautomation.com/Patchcnnvd
http://www.securityfocus.com/bid/98630 cnnvd
https://ics-cert.us-cert.gov/advisories/ICSA-17-115-04 cnnvd
http://www.securitytracker.com/id/1038546 enisa_euvd
https://ics-cert.us-cert.gov/advisories/ICSA-17-115-04 enisa_euvd
http://www.securitytracker.com/id/1038546 nvd
https://ics-cert.us-cert.gov/advisories/ICSA-17-115-04PatchThird Party AdvisoryUS Government Resourcenvd

scry

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