HOME VULNERABILITIESCVE-2019-18634

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CVE-2019-18634

CWE-787Published: January 29, 2020· Updated: Jun 17, 2026

7.8

CVSS v3.1

Official Description

In Sudo before 1.8.26, if pwfeedback is enabled in /etc/sudoers, users can trigger a stack-based buffer overflow in the privileged sudo process. (pwfeedback is a default setting in Linux Mint and elementary OS; however, it is NOT the default for upstream and many other packages, and would exist only if enabled by an administrator.) The attacker needs to deliver a long string to the stdin of getln() in tgetpass.c.

Technical Analysis

CVE-2019-18634 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

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 7.8.

A proof-of-concept (PoC) exploit exists for CVE-2019-18634. While not yet confirmed in active campaigns, the availability of PoC code increases exploitation risk substantially.

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 VectorLocal

Attack ComplexityLow

Privileges Req.Low

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Debian1 product(s)

debian linux

sudo_project1 product(s)

sudo

Source: NVD CPE · 4 total CPE entries

Exploit & PoC Resources

POC AVAILABLEProof-of-concept code exists

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

Security advisories & exploits

Official NIST entry

CVE Program entry

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttp://packetstormsecurity.com/files/156174/Slackware-Security-Advisory-sudo-Updates.html

ADVISORYhttp://packetstormsecurity.com/files/156189/Sudo-1.8.25p-Buffer-Overflow.html

ADVISORYhttp://seclists.org/fulldisclosure/2020/Jan/40

ADVISORYhttp://www.openwall.com/lists/oss-security/2020/01/30/6

ADVISORYhttp://www.openwall.com/lists/oss-security/2020/01/31/1

ADVISORYhttp://www.openwall.com/lists/oss-security/2020/02/05/2

ADVISORYhttp://www.openwall.com/lists/oss-security/2020/02/05/5

ADVISORYhttps://lists.debian.org/debian-lts-announce/2020/02/msg00002.html

ADVISORYhttps://seclists.org/bugtraq/2020/Feb/2

ADVISORYhttps://seclists.org/bugtraq/2020/Feb/3

ADVISORYhttps://seclists.org/bugtraq/2020/Jan/44

ADVISORYhttps://support.apple.com/kb/HT210919

ADVISORYhttps://www.debian.org/security/2020/dsa-4614

ADVISORYhttps://www.sudo.ws/alerts/pwfeedback.html

ADVISORYhttps://www.sudo.ws/security.html

ADVISORYhttp://packetstormsecurity.com/files/156174/Slackware-Security-Advisory-sudo-Updates.html

ADVISORYhttp://packetstormsecurity.com/files/156189/Sudo-1.8.25p-Buffer-Overflow.html

ADVISORYhttp://seclists.org/fulldisclosure/2020/Jan/40

ADVISORYhttp://www.openwall.com/lists/oss-security/2020/01/30/6

ADVISORYhttp://www.openwall.com/lists/oss-security/2020/01/31/1

ADVISORYhttp://www.openwall.com/lists/oss-security/2020/02/05/2

ADVISORYhttp://www.openwall.com/lists/oss-security/2020/02/05/5

ADVISORYhttps://lists.debian.org/debian-lts-announce/2020/02/msg00002.html

ADVISORYhttps://seclists.org/bugtraq/2020/Feb/2

ADVISORYhttps://seclists.org/bugtraq/2020/Feb/3

ADVISORYhttps://seclists.org/bugtraq/2020/Jan/44

ADVISORYhttps://support.apple.com/kb/HT210919

ADVISORYhttps://www.debian.org/security/2020/dsa-4614

ADVISORYhttps://www.sudo.ws/alerts/pwfeedback.html

ADVISORYhttps://www.sudo.ws/security.html

All References (52)

→

http://lists.opensuse.org/opensuse-security-announce/2020-02/msg00029.html

→

http://packetstormsecurity.com/files/156174/Slackware-Security-Advisory-sudo-Updates.htmlThird Party Advisory · VDB Entry

→

http://packetstormsecurity.com/files/156189/Sudo-1.8.25p-Buffer-Overflow.htmlThird Party Advisory · VDB Entry

→

http://seclists.org/fulldisclosure/2020/Jan/40Mailing List · Third Party Advisory

→

http://www.openwall.com/lists/oss-security/2020/01/30/6Mailing List · Third Party Advisory

→

http://www.openwall.com/lists/oss-security/2020/01/31/1Mailing List · Third Party Advisory

→

http://www.openwall.com/lists/oss-security/2020/02/05/2Third Party Advisory

→

http://www.openwall.com/lists/oss-security/2020/02/05/5Exploit · Third Party Advisory

→

https://access.redhat.com/errata/RHSA-2020:0487

→

https://access.redhat.com/errata/RHSA-2020:0509

→

https://access.redhat.com/errata/RHSA-2020:0540

→

https://access.redhat.com/errata/RHSA-2020:0726

→

https://lists.debian.org/debian-lts-announce/2020/02/msg00002.htmlMailing List · Third Party Advisory

→

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I6TKF36KOQUVJNBHSVJFA7BU3CCEYD2F/

→

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IY6DZ7WMDKU4ZDML6MJLDAPG42B5WVUC/

Quick Facts

CVE IDCVE-2019-18634

CVSS Score7.8 / 10

SeverityHIGH

WeaknessCWE-787

CISA KEVNo

ExploitPOC

Affected2 vendor(s)

PublishedJan 29, 2020

Related CVEs (CWE-787)

Recommended Actions

→Apply vendor patches immediately
→Monitor CVE-2019-18634 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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