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Fencer Vulns
medium 6.5

CVE-2020-15117 json

Denial of Service in Synergy

published 2020-07-15 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-7223

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

In Synergy before version 1.12.0, a Synergy server can be crashed by receiving a kMsgHelloBack packet with a client name length set to 0xffffffff (4294967295) if the servers memory is less than 4 GB. It was verified that this issue does not cause a crash through the exception handler if the available memory of the Server is more than 4GB.

Patch / fix

  • symless synergy 1.12.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-15117 updated cvss 7.5

synergy: kMsgHelloBack packet with client name length of 0xffffffff causing DoS

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.49% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Affected products

  • symless synergy-core

Classification

Weakness
  • CWE-755 Improper Handling of Exceptional Conditions
  • CWE-754 Improper Check for Unusual or Exceptional Conditions

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.