CVE Intelligence
High Insecure deserialization exploit reference

CVE-2025-59050 — Greenshot — Insecure .NET deserialization via WM_COPYDATA enables local code execution

Greenshot is an open source Windows screenshot utility. Greenshot 1.3.300 and earlier deserializes attacker-controlled data received in a WM_COPYDATA message using BinaryFormatter.Deserialize without prior validation or authentication, allowing a local process at the same integrity level to trigger arbitrary code execution inside the Greenshot process. The vulnerable logic resides in a WinForms WndProc handler for WM_COPYDATA (message 74) that copies the supplied bytes into a MemoryStream and invokes BinaryFormatter.Deserialize, and only afterward checks whether the specified channel is authorized. Because the authorization check occurs after deserialization, any gadget chain embedded in the serialized payload executes regardless of channel membership. A local attacker who can send WM_COPYDATA to the Greenshot main window can achieve in-process code execution, which may aid evasion of application control policies by running payloads within the trusted, signed Greenshot.exe process. This issue is fixed in version 1.3.301. No known workarounds exist.

Published Sep 16, 2025 · Updated Oct 19, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.3% (30-day exploitation probability)+3
  • Technical severity (high)+6
  • CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.29%
ahead of 20% of scored CVEs · Oct 19, 2026
Affects
Getgreenshot
Greenshot
CVSS base
7.8
High · 3 source(s)
Prioritization reference: 8.4 provisional

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Getgreenshot Greenshot, Greenshot Greenshot).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Search available logs for exploit probes matching the vulnerability class (insecure deserialization), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Getgreenshot Greenshot < 1.3.301 Vulnerable NIST National Vulnerability Database
Greenshot Greenshot version < 1.3.301 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.4 CVSS 3.1 High 2.5 5.9 security-advisories@github.com via NIST National Vulnerability Database
8.4 CVSS 3.1 High — — GitHub_M via CVE Program (cve.org) e CISA ADP
7.8 CVSS 3.1 High 1.8 5.9 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)
Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 8.4 (security-advisories@github.com via NIST National Vulnerability Database) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-502 · Deserialization of Untrusted Data

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
  • Monitor serialized objects in requests and unexpected processes spawned by the runtime.
endpoint telemetry (EDR)application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · greenshot/greenshot
    Oct 19, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 19, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 19, 2026
  • Fix documented
    Oct 19, 2026 · NIST National Vulnerability Database
  • Affected products added · getgreenshot/greenshot
    Oct 19, 2026 · NIST National Vulnerability Database
  • CVSS changed · 7.8
    Oct 19, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 19, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 19, 2026 · Alertas do Telegram
  • 2025
  • CVE published
    Sep 16, 2025 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 19, 2026 – Oct 19, 2026
  • 1× Official description updated · Oct 19, 2026 – Oct 19, 2026

References

2 on the record

Elsewhere on this site

Getgreenshot
every CVE for this vendor
Insecure deserialization
same class
CWE-502
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-25792 Greenshot Vulnerable to OS Command Injection via ExternalCommand Plugin Mar 20, 2026
  • CVE-2026-22035 Greenshot Vulnerable to OS Command Injection via ExternalCommand Plugin Jan 7, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-59050 is "Greenshot — Insecure .NET deserialization via WM_COPYDATA enables local code execution", rated High. It affects Greenshot (Getgreenshot); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.29% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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