HOMEVULNERABILITIESCVE-2016-2563
CRITICALPOC

CVE-2016-2563

CWE-119Published: April 7, 2016· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

Stack-based buffer overflow in the SCP command-line utility in PuTTY before 0.67 and KiTTY 0.66.6.3 and earlier allows remote servers to cause a denial of service (stack memory corruption) or execute arbitrary code via a crafted SCP-SINK file-size response to an SCP download request.

NVD Source

Technical Analysis

CVE-2016-2563 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

A proof-of-concept (PoC) exploit exists for CVE-2016-2563. While not yet confirmed in active campaigns, the availability of PoC code increases exploitation risk substantially.

From a weakness classification perspective (CWE-119): Buffer overflow vulnerabilities can lead to arbitrary code execution or denial of service by corrupting adjacent memory.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

9bis1 product(s)
kitty
simon_tatham1 product(s)
putty
Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

POC AVAILABLEProof-of-concept code exists
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

All References (14)

Quick Facts

CVE IDCVE-2016-2563
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-119
CISA KEVNo
ExploitPOC
Affected2 vendor(s)
PublishedApr 7, 2016

Related CVEs (CWE-119)

Recommended Actions

  • Apply vendor patches immediately
  • Monitor CVE-2016-2563 in threat intel feeds
  • Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.