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Disable sec_error_reused_issuer_and_serial

  • 5 replies
  • 1 has this problem
  • 4 views
  • Last reply by MHammett

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I need a way to disable the "sec_error_reused_issuer_and_serial" block. I don't have Kaspersky. Deleting the file I've seen mentioned will do no good because the error will just come back next time I visit the same servers.


When will people developing browsers realize that there are people out there that access more than cat videos and porn? Some of us manage an array of embedded devices that can't be updated?

I need a way to disable the "sec_error_reused_issuer_and_serial" block. I don't have Kaspersky. Deleting the file I've seen mentioned will do no good because the error will just come back next time I visit the same servers. When will people developing browsers realize that there are people out there that access more than cat videos and porn? Some of us manage an array of embedded devices that can't be updated?

All Replies (5)

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It’s the server owner’s responsibility to make their servers available for all browsers, and hence, their (unique) certificates. And usually, if they work for Firefox, they work for any browser, not the other way around (luckily).

Do you use any other security product "interfering" with your connection? What file did you delete?

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They aren't "servers" in the traditional sense. They're embedded devices.

HVAC controllers, switches, routers, DSLAMs, printers, etc., etc. are all the types of devices that you don't exactly have the ability to influence the certificate or encryption method.

I didn't delete anything, but when searching the forum for that error, several people were able to restore their use of various websites by deleting a file.

Chrome and Java have done similar, "I'm sorry, you can't work around this" things in the past.

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Does this help? SEC_ERROR_REUSED_ISSUER_AND_SERIAL https://www.bing.com/search?q=sec_error_reused_issuer_and_serial

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Is the firmware for these devices up to date and able to cope with modern browser / security demands, in particular with regard to unique certificates? The sec_error_reused_issuer_and_serial error used to occur for older routers and other hardware and should now rarely occur, hence the question.

As a matter of fact, the error message was covered in an older KB article that you should still be able to read, which may contain a workaround too.

Yet again, what file are you talking about? Could it be cert9.db? If so, delete key4.db too.

Keep in mind some malware related software such as Spybot or MalwareBytes may contain features such as Tea Timer or Web Shield that affect secure connections.

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The problem with that is that I'd need to have users delete that file multiple times a day as they move around.


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The cause is that the self generated certificate of the site you are browsing have the same serial number of a previously stored certificate (another Web site you already visited and manually added an exception for).

To resolve this matter, you need to delete the Firefox certificate database file. Simply delete the “cert8.db” file under your profile under that path :

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