CVE-2016-7152: The HTTPS protocol does not consider the role of the TCP congestion window in providing information about cont

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MEDIUM 5.3REMOTEWATCHLISTMITIGATEMITIGATEMITIGATE

CVE-2016-7152 is a medium-severity flaw (CVSS 5.3) affecting opera, safari, firefox. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The HTTPS 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.

Why this priority

EPSS top 4%: very likely to be exploited
Remotely exploitable, no login, no user action
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	12.8% (top 4%)
CISA exploited list	No
Weakness	CWE-200
Published	2016-09-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: apple · google · microsoft · mozilla · opera

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2016-09-06 10:59 UTCPublished CVE record published
2026-06-17 00:52 UTCUpdated Record last modified

opera opera MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy opera || rpm -q opera || opera --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

apple safari MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy safari || rpm -q safari || safari --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

mozilla firefox MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy firefox || rpm -q firefox || firefox --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

microsoft edge MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy edge || rpm -q edge || edge --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

microsoft internet explorer MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy internet-explorer || rpm -q internet-explorer || internet-explorer --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

google chrome MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy chrome || rpm -q chrome || chrome --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2016-7152?

opera: mitigate or apply the listed mitigation; safari: mitigate or apply the listed mitigation; firefox: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2016-7152 being exploited?

CVE-2016-7152 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2016-7152 affect?

CVE-2016-7152 affects opera, safari, firefox. Severity is medium (CVSS 5.3). The HTTPS 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

How urgent is CVE-2016-7152?

Priority 53/100. EPSS top 4%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Microsoft Edge vulnerabilities · Safari vulnerabilities · Google Chrome vulnerabilities · Mozilla Firefox vulnerabilities · Internet Explorer vulnerabilities · Apple Safari and WebKit vulnerabilities

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CVE-2019-12278 MEDIUM 4.3 DOWNGRADE Opera through 53 on Android allows Address Bar Spoofing
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CVE-2009-2068 MEDIUM 5.8 DOWNGRADE Google Chrome detects http content in https web pages only when the top-level frame uses https, which allows m
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References

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