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Fencer Intel
high 7.8

CVE-2019-18634 in the critical feed json

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 pro…

published 6y ago modified 4mo ago also EUVD-2019-8357

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
19.3%
EPSS 19.3% chance of exploitation in 30 days, percentile 97%
public exploits
2
Exploit-DB

Summary

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.

Patch / fix

  • sudo_project sudo 1.8.26
  • sudo Debian 14, Debian 13, Debian 12 1.8.31-1

debian advisories DEBIAN-CVE-2019-18634

  • sudo Ubuntu 16.04 LTS 1.8.16-0ubuntu1.9
  • sudo Ubuntu 18.04 LTS 1.8.21p2-3ubuntu1.2
  • sudo Ubuntu Pro 14.04 LTS 1.8.9p5-1ubuntu1.5+esm3

ubuntu advisories UBUNTU-CVE-2019-18634

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • sudo RHEL 6 1.8.6p3-29.el6_10.3
  • sudo RHEL 7 1.8.23-4.el7_7.2
  • sudo RHEL 8 1.8.25p1-8.el8_1.1
  • sudo RHEL 8.0 E4S 1.8.25p1-4.el8_0.3

red hat advisories RHSA-2020:0726RHSA-2020:0540RHSA-2020:0509RHSA-2020:0487

  • sudo SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 1.8.27-4.3.1
  • sudo SLES for SAP 15, SLES 15-LTSS, SLE Module for Basesystem 15 SP1 +3 more 1.8.22-4.9.1
  • sudo SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +1 more 1.8.10p3-10.26.1
  • sudo SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES 12 SP4 +8 more 1.8.20p2-3.17.1
  • sudo SLES for SAP 12 SP1, SLES 12 SP1-LTSS 1.8.10p3-2.32.1

suse advisories SUSE-SU-2020:0409-1SUSE-SU-2020:0408-1SUSE-SU-2020:0407-1SUSE-SU-2020:0406-1SUSE-SU-2020:0390-1

  • sudo openSUSE Tumbleweed 1.9.7p2-1.4
  • sudo openSUSE Leap 15.1 1.8.22-lp151.5.6.1

opensuse advisories openSUSE-SU-2024:11413-1openSUSE-SU-2020:0244-1

  • sudo Alpine 3.10 1.8.27-r2
  • sudo Alpine 3.11 1.8.29-r2
  • sudo Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 1.8.31-r0
  • sudo Alpine 3.8 1.8.23-r4
  • sudo Alpine 3.9 1.8.25_p1-r3

alpine advisories ALPINE-CVE-2019-18634

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • sudo Arch Linux 1.8.31-1

arch linux advisories AVG-1093

Is CVE-2019-18634 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-18634 updated cvss 7.8

sudo: Stack based buffer overflow when pwfeedback is enabled

  • Red Hat Enterprise Linux BaseOS (v. 8) sudo 1.8.25p1-8.el8_1.1
    fixed: vendor fix RHSA-2020:0487
  • Red Hat Enterprise Linux BaseOS E4S (v. 8.0) sudo 1.8.25p1-4.el8_0.3
    fixed: vendor fix RHSA-2020:0509
  • Red Hat Enterprise Linux Client (v. 7) sudo 1.8.23-4.el7_7.2 Red Hat Enterprise Linux Client Optional (v. 7) sudo-devel 1.8.23-4.el7_7.2, sudo-debuginfo 1.8.23-4.el7_7.2 Red Hat Enterprise Linux ComputeNode (v. 7) sudo 1.8.23-4.el7_7.2 Red Hat Enterprise Linux ComputeNode Optional (v. 7) sudo-devel 1.8.23-4.el7_7.2, sudo-debuginfo 1.8.23-4.el7_7.2
    fixed: vendor fix RHSA-2020:0540
  • Red Hat Enterprise Linux Desktop (v. 6) sudo 1.8.6p3-29.el6_10.3 Red Hat Enterprise Linux Desktop Optional (v. 6) sudo-devel 1.8.6p3-29.el6_10.3, sudo-debuginfo 1.8.6p3-29.el6_10.3 Red Hat Enterprise Linux HPC Node (v. 6) sudo 1.8.6p3-29.el6_10.3 Red Hat Enterprise Linux HPC Node Optional (v. 6) sudo-devel 1.8.6p3-29.el6_10.3, sudo-debuginfo 1.8.6p3-29.el6_10.3 Red Hat Enterprise Linux Server (v. 6) sudo 1.8.6p3-29.el6_10.3
    fixed: vendor fix RHSA-2020:0726
  • Red Hat Enterprise Linux Server (v. 7) sudo 1.8.23-4.el7_7.2
    fixed: vendor fix RHSA-2020:0540
  • Red Hat Enterprise Linux Server Optional (v. 6) sudo-devel 1.8.6p3-29.el6_10.3, sudo-debuginfo 1.8.6p3-29.el6_10.3
    fixed: vendor fix RHSA-2020:0726
  • Red Hat Enterprise Linux Server Optional (v. 7) sudo-devel 1.8.23-4.el7_7.2, sudo-debuginfo 1.8.23-4.el7_7.2
    fixed: vendor fix RHSA-2020:0540
  • Red Hat Enterprise Linux Workstation (v. 6) sudo 1.8.6p3-29.el6_10.3
    fixed: vendor fix RHSA-2020:0726
show 4 more
  • Red Hat Enterprise Linux Workstation (v. 7) sudo 1.8.23-4.el7_7.2
    fixed: vendor fix RHSA-2020:0540
  • Red Hat Enterprise Linux Workstation Optional (v. 6) sudo-devel 1.8.6p3-29.el6_10.3, sudo-debuginfo 1.8.6p3-29.el6_10.3
    fixed: vendor fix RHSA-2020:0726
  • Red Hat Enterprise Linux Workstation Optional (v. 7) sudo-devel 1.8.23-4.el7_7.2, sudo-debuginfo 1.8.23-4.el7_7.2
    fixed: vendor fix RHSA-2020:0540
  • Red Hat Enterprise Linux 5 sudo
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. Published
  2. First public exploit (EDB-47995)

Exploit prediction

19.28% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-48052 Sudo 1.8.25p - 'pwfeedback' Buffer Overflow local, 2020-02-06
  • EDB-47995 Sudo 1.8.25p - 'pwfeedback' Buffer Overflow (PoC) dos, 2020-02-04
  • sudo.ws https://www.sudo.ws/alerts/pwfeedback.html referenced PoC, tagged "exploit" by a source, unverified
  • openwall.com http://www.openwall.com/lists/oss-security/2020/02/05/5 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.