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CVE-2018-8929· NVD / CVE Program· CNA synology

Improper restriction of communication channel to intended endpoints vulnerability in HTTP daemon in Synology SSL VPN Client before 1.2.4-022

Improper restriction of communication channel to intended endpoints vulnerability in HTTP daemon in Synology SSL VPN Client before 1.2.4-0224 allows remote attackers to conduct man-in-the-middle attacks via a crafted payload.

HighCVSS 8.1 · v3.0—No exploit No fix recorded
Published
Jul 6, 2018
Updated
Jun 16, 2026
EPSS
0.8% · 53th percentile
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Report tools

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Action score

32

Monitor

Low priority for now.

CVSS
32 / 40 · 8.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CNA vs NVD score

NVD
8.1
CNA · synology
7.3
0.8 point gap

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
synologyssl vpn client

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • synology ssl vpn clientbefore 1.2.4-0224

Versions reported by the vendor

Affected version ranges reported by the assigning authority (synology). Independent of NVD's CPE analysis and usually ahead of it.

  • Synology SSL VPN Client

    • unspecified and later · before 1.2.4-0224affected

Same product

synology: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-47961A plaintext storage of a password vulnerability in Synology SSL VPN Client before 1.4.5-0684 allows remote attackers to access or influence
    32Monitor
  • CVE-2018-13283Lack of administrator control over security vulnerability in client.cgi in Synology SSL VPN Client before 1.2.5-0226 allows remote attackers
    29Monitor
  • CVE-2021-47960A files or directories accessible to external parties vulnerability in Synology SSL VPN Client before 1.4.5-0684 allows remote attackers to
    26Monitor
  • CVE-2023-5748Buffer copy without checking size of input ('Classic Buffer Overflow') vulnerability in cgi component in Synology SSL VPN Client before 1.4.
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-319 · Cleartext Transmission of Sensitive Information

CVSS vector

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records