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Public proof of conceptFix available

CVE-2019-18634

A public proof of concept exists; no exploitation attested.

  • Published2020-01-29
  • WeaknessCWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2020-01-2918:15CVE publishedNVD
  2. 2020-02-04Exploit-DB entryExploit-DB

Versions per branch

NVD
Debian debian linux
BranchAffectedFixed in
8.0= 8.0no fix published
9.0= 9.0no fix published
10.0= 10.0no fix published
Sudo project sudo
BranchAffectedFixed in
1.x≥ 1.7.1, < 1.8.261.8.26

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • sudoUbuntu:Pro:14.04:LTSall versions · fixed in 1.8.9p5-1ubuntu1.5+esm3
  • sudoUbuntu:18.04:LTSall versions · fixed in 1.8.21p2-3ubuntu1.2
  • sudoUbuntu:16.04:LTSall versions · fixed in 1.8.16-0ubuntu1.9
  • sudoSUSE:OpenStack Cloud Crowbar 8all versions · fixed in 1.8.20p2-3.17.1
  • sudoSUSE:OpenStack Cloud 8all versions · fixed in 1.8.20p2-3.17.1
  • sudoSUSE:OpenStack Cloud 7all versions · fixed in 1.8.10p3-10.26.1
  • sudoSUSE:Linux Enterprise Software Development Kit 12 SP5all versions · fixed in 1.8.27-4.3.1
  • sudoSUSE:Linux Enterprise Software Development Kit 12 SP4all versions · fixed in 1.8.20p2-3.17.1

57 more package ranges on OSV.dev

Vendor advisories

  • CVE-2019-18634 Red Hat Product Security308 products fixed

    sudo: Stack based buffer overflow when pwfeedback is enabled

  • RHSA-2020:0726 Red Hat Product Security46 products fixed

    Red Hat Security Advisory: sudo security update

  • RHSA-2020:0540 Red Hat Product Security44 products fixed

    Red Hat Security Advisory: sudo security update

  • RHSA-2020:0487 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: sudo security update

  • RHSA-2020:0509 Red Hat Product Security7 products fixed

    Red Hat Security Advisory: sudo security update

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2020:0726 · 46 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  2. Workaround from the vendor Red Hat Product Security RHSA-2020:0726 · 46 productsPlease follow the steps bellow as mitigation: 1. Check the default properties set for sudo by running: ~~~ $ sudo -l [sudo] password for user: Matching Defaults entries for users on localhost: !visiblepw, pwfeedback, always_set_home, match_group_by_gid, always_query_group_…

Advisories and patches

Detection

read 2026-11-01 01:02 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
EDB-47995EDB-48052
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.8read 2026-10-23
  • NVDCVSS 2.04.6read 2026-10-23
  • NVDweakness (CWE)CWE-787read 2026-10-23
  • FIRST EPSSEPSS score19.3 %read 2026-11-04
  • PoC-in-GitHubproof of concept14known since 2026-11-01
  • Exploit-DBdetectionread 2026-11-04
  • OSVaffected packages—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2020-01-29
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2019-18634?

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.

Is CVE-2019-18634 actively exploited?

Active exploitation of CVE-2019-18634 has not been confirmed. Its EPSS score was 19.3% on 2026-11-04, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-18634?

CVE-2019-18634 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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