# WPlease log out of browser, for Security reasons after exiting EMail. Why? Whats the vulnerability?
**URL:** https://boards.straightdope.com/t/wplease-log-out-of-browser-for-security-reasons-after-exiting-email-why-whats-the-vulnerability/687540
**Category:** Factual Questions
**Created:** [May 2, 2014, 10:02pm UTC](https://boards.straightdope.com/t/wplease-log-out-of-browser-for-security-reasons-after-exiting-email-why-whats-the-vulnerability/687540 "2014-05-02T22:02:40Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@aceplace57](https://boards.straightdope.com/u/aceplace57)
#### Post date: [May 2, 2014, 10:02pm UTC](https://boards.straightdope.com/t/wplease-log-out-of-browser-for-security-reasons-after-exiting-email-why-whats-the-vulnerability/687540/1 "2014-05-02T22:02:40Z")
Every time I log out of my web based Email at work a page size banner reminds me to exit my browser for “security reasons”.
Why???
I try hitting the back button and it doesn’t go back into my GMail. I get a gmail sign in page. Safe and secure, as it should be.
If I was really paranoid then I could close the Tab. Still seems like a waste of time.
Whats kind of magical voodoo would a hacker need to get into my email if I didn’t close my browser? Whats this serious vulnerability that requires me to close my browser?
> [@](#):
>
> Log-out successful
>
> You have been successfully logged out of the single sign-on service. Learn more.
>
> For security reasons, please also exit your web browser.
---
### Author:  [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)
#### Post date: [May 2, 2014, 10:07pm UTC](https://boards.straightdope.com/t/wplease-log-out-of-browser-for-security-reasons-after-exiting-email-why-whats-the-vulnerability/687540/2 "2014-05-02T22:07:58Z")
Some browsers don’t clear the cookies when the tab is closed. Someone in a public place can reopen the tab (or just go to the website) and have access/to the mail.
---
### Author:  [@Reply](https://boards.straightdope.com/u/Reply)
#### Post date: [May 2, 2014, 10:31pm UTC](https://boards.straightdope.com/t/wplease-log-out-of-browser-for-security-reasons-after-exiting-email-why-whats-the-vulnerability/687540/3 "2014-05-02T22:31:56Z")
It makes it a tiny bit harder for an unauthorized person to read your session cookies, history, and cache.
Gmail is designed to lock you out after you sign out, but not all email services do that (the old pages may still be cached and viewable). It’s a good practice to get into, I suppose, even if it’s not really all that helpful against a determined attacker. At least it’s one more layer of protection against casual snoopers.