HOMEVULNERABILITIESCVE-2020-9366
CRITICAL

CVE-2020-9366

CWE-787Published: February 24, 2020· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

A buffer overflow was found in the way GNU Screen before 4.8.0 treated the special escape OSC 49. Specially crafted output, or a special program, could corrupt memory and crash Screen or possibly have unspecified other impact.

NVD Source

Technical Analysis

CVE-2020-9366 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.

From a weakness classification perspective (CWE-787): Out-of-bounds write vulnerabilities can lead to data corruption, crashes, or arbitrary code execution.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

gnu1 product(s)
screen
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
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Official Patches & Advisories

PATCHhttps://lists.gnu.org/archive/html/screen-devel/2020-02/msg00007.html
PATCHhttps://www.openwall.com/lists/oss-security/2020/02/06/3
PATCHhttps://lists.gnu.org/archive/html/screen-devel/2020-02/msg00007.html
PATCHhttps://www.openwall.com/lists/oss-security/2020/02/06/3
ADVISORYhttp://www.openwall.com/lists/oss-security/2020/02/25/1
ADVISORYhttps://security.gentoo.org/glsa/202003-62
ADVISORYhttp://www.openwall.com/lists/oss-security/2020/02/25/1
ADVISORYhttps://security.gentoo.org/glsa/202003-62

All References (8)

→
http://www.openwall.com/lists/oss-security/2020/02/25/1Mailing List · Third Party Advisory
→
https://lists.gnu.org/archive/html/screen-devel/2020-02/msg00007.htmlMailing List · Patch · Release Notes · Vendor Advisory
→
https://security.gentoo.org/glsa/202003-62Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2020/02/06/3Mailing List · Patch · Release Notes
→
http://www.openwall.com/lists/oss-security/2020/02/25/1Mailing List · Third Party Advisory
→
https://lists.gnu.org/archive/html/screen-devel/2020-02/msg00007.htmlMailing List · Patch · Release Notes · Vendor Advisory
→
https://security.gentoo.org/glsa/202003-62Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2020/02/06/3Mailing List · Patch · Release Notes

Quick Facts

CVE IDCVE-2020-9366
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-787
CISA KEVNo
Affected1 vendor(s)
PublishedFeb 24, 2020

Related CVEs (CWE-787)

CVE-2026-42369
10.0
CVE-2004-0978
10.0
CVE-2018-10718
10.0
CVE-2009-2466
10.0
CVE-2026-4746
10.0
CVE-2012-0751
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-9366 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. CVE data is provided under the NVD usage policy.
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