# What is CVE-2016-7153? > CVE-2016-7153 is a medium-severity flaw (CVSS 5.3) in Edge from Microsoft, published on 6 September 2016. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 13%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2016-7153 ## At a glance - **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. - **Precursor Intelligence risk score:** 26 out of 100 (Low); action: Monitor. Kept up to date as the evidence changes. - **Severity:** Medium (CVSS 5.3 out of 10) - **Known to be exploited:** No, not on the list of flaws known to be exploited today - **Chance of use in the next 30 days:** 13% (latest exploit-likelihood forecast) - **Published:** 6 September 2016 - **Record last updated:** 12 April 2025 - **Main product:** Edge from Microsoft - **Affected products:** 6 ## What is CVE-2016-7153? In plain terms It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read some data. ### The official description The HTTP/2 protocol does not consider the role of the TCP congestion window in providing information about content length, which makes it easier for remote attackers to obtain cleartext data by leveraging a web-browser configuration in which third-party cookies are sent, aka a "HEIST" attack. ### What kind of flaw is it? - CWE-200: Exposure of Sensitive Information to an Unauthorized Actor ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Easy: no special conditions - Login needed first: No login needed - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can read some data Severity vector: `CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N` ## Is CVE-2016-7153 being exploited? Not that we know of It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 13%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 14%, 14%, 14%, 13%, 13%, 13%, 13%. ### Timeline - 6 September 2016: Published - 12 April 2025: Record last updated - 16 June 2026: Exploit likelihood jumped ### How Precursor Intelligence ranks it CVE-2016-7153 scores **26 out of 100 (Low)**, with the action "Monitor". Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less: - Evidence it is being exploited: biggest factor - How severe it is: strong factor - How widely exposed it is: smaller factor - Threat activity around it: smaller factor 85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it. ## Who is affected by CVE-2016-7153? The published record lists 6 products. - [Edge](https://www.precursorintelligence.com/product/microsoft/edge) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Application): version not specified - [Chrome](https://www.precursorintelligence.com/product/google/chrome) by [Google](https://www.precursorintelligence.com/vendors/google) (Application): version not specified - [Firefox](https://www.precursorintelligence.com/product/mozilla/firefox) by [Mozilla](https://www.precursorintelligence.com/vendors/mozilla) (Application): all versions - [Internet Explorer](https://www.precursorintelligence.com/product/microsoft/internet_explorer) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Application): version not specified - [Opera Browser](https://www.precursorintelligence.com/product/opera/opera_browser) by [Opera](https://www.precursorintelligence.com/vendors/opera) (Application): version not specified - [Safari](https://www.precursorintelligence.com/product/apple/safari) by [Apple](https://www.precursorintelligence.com/vendors/apple) (Application): all versions ## How do I fix CVE-2016-7153? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list. 2. **Apply the vendor’s fix.** Install the latest update from the vendor. The references list where the vendor has published details. 3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in. 4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood. ### References - [arstechnica.com](http://arstechnica.com/security/2016/08/new-attack-steals-ssns-e-mail-addresses-and-more-from-https-pages/) (Technical description) - [securityfocus.com](http://www.securityfocus.com/bid/92773) - [securitytracker.com](http://www.securitytracker.com/id/1036741) - [securitytracker.com](http://www.securitytracker.com/id/1036742) - [securitytracker.com](http://www.securitytracker.com/id/1036743) - [securitytracker.com](http://www.securitytracker.com/id/1036744) - [securitytracker.com](http://www.securitytracker.com/id/1036745) - [securitytracker.com](http://www.securitytracker.com/id/1036746) - [tom.vg](https://tom.vg/papers/heist_blackhat2016.pdf) (Technical description) ## Questions ### What is CVE-2016-7153? CVE-2016-7153 is a medium-severity flaw in Edge from Microsoft, published on 6 September 2016. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read some data. ### How serious is CVE-2016-7153? It scores 5.3 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2016-7153 is 26 out of 100, which is Low. Its action is "Monitor". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. ### Is CVE-2016-7153 being exploited? It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 13%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2016-7153 affect? For Edge from Microsoft: version not specified. The record lists 6 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2016-7153? Install the update the vendor names in its advisory. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2016-7153 affect you? Precursor Intelligence keeps checking for you: - **Tell us what you run.** Pick your software from a list, or let us work it out from your website. - **We match it to every flaw.** Over 400,000 published flaws, checked against your list. - **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it. - **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact