CVE-2015-7756: The encryption implementation in Juniper ScreenOS 6.2.0r15 through 6.2.0r18, 6.3.0r12 before 6.3.0r12b, 6.3.0r

Routine

MEDIUM 5.0MITIGATE

CVE-2015-7756 is a medium-severity flaw (CVSS 5.0) affecting screenos. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The encryption implementation in Juniper ScreenOS 6.2.0r15 through 6.2.0r18, 6.3.0r12 before 6.3.0r12b, 6.3.0r13 before 6.3.0r13b, 6.3.0r14 before 6.3.0r14b, 6.3.0r15 before 6.3.0r15b, 6.3.0r16 before 6.3.0r16b, 6.3.0r17 before 6.3.0r17b, 6.3.0r18 before 6.3.0r18b, 6.3.0r19 before 6.3.0r19b, and 6.3.0r20 before 6.3.0r21 makes it easier for remote attackers to discover the plaintext content of VPN sessions by sniffing the network for ciphertext da

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	2.5% (top 15%)
CISA exploited list	No
Weakness	CWE-310
Published	2015-12-19
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: juniper

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

Am I affected?

Timeline

2015-12-19 14:59 UTCPublished CVE record published
2026-06-17 00:33 UTCUpdated Record last modified

juniper screenos MITIGATE

Affected: 6.2.0r15 · 6.2.0r16 · 6.2.0r17 · 6.2.0r18 · 6.3.0 r12 · 6.3.0 r14 · 6.3.0 r15 · 6.3.0 r16

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.2.0r15

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2015-7756?

screenos: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2015-7756 being exploited?

CVE-2015-7756 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-2015-7756 affect?

CVE-2015-7756 affects screenos. Severity is medium (CVSS 5.0). The encryption implementation in Juniper ScreenOS 6.2.0r15 through 6.2.0r18, 6.3.0r12 before 6.3.0r12b, 6.3.0r13 before 6.3.0r13b, 6.3.0r14 before 6.3.0r14b, 6.3.0r15 before 6.3.0r15b, 6.3.0r16 before 6.3.0r16b, 6.3.0r17 before 6.3.0r17b, 6

How urgent is CVE-2015-7756?

Priority 39/100. No elevated risk signals yet.

Software pages

Juniper Junos vulnerabilities

Related CVEs

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CVE-2017-2339 HIGH 8.4 MITIGATE A persistent cross site scripting vulnerability in NetScreen WebUI of Juniper Networks Juniper NetScreen Firew
CVE-2017-2338 HIGH 8.4 MITIGATE A persistent cross site scripting vulnerability in NetScreen WebUI of Juniper Networks Juniper NetScreen Firew
CVE-2017-2337 HIGH 8.4 MITIGATE A persistent cross site scripting vulnerability in NetScreen WebUI of Juniper Networks Juniper NetScreen Firew
CVE-2017-2336 CRITICAL 9.6 MITIGATE A reflected cross site scripting vulnerability in NetScreen WebUI of Juniper Networks Juniper NetScreen Firewa

References

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