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Fencer Vulns
high 7.4

CVE-2021-32066 json

An issue was discovered in Ruby through 2.6.7, 2.7.x through 2.7.3, and 3.x through 3.0.1.

published 2021-08-01 5 y ago modified 2026-09-08 2 mo ago also BIT-ruby-2021-32066 , BIT-ruby-min-2021-32066 , EUVD-2021-18928 , JLSEC-2026-1285

cvss
7.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.9%
EPSS 2.9% chance of exploitation in 30 days, percentile 87%
public exploits
0
none known

Summary

An issue was discovered in Ruby through 2.6.7, 2.7.x through 2.7.3, and 3.x through 3.0.1. Net::IMAP does not raise an exception when StartTLS fails with an an unknown response, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a "StartTLS stripping attack."

Patch / fix

  • bitnami ruby 2.6.8, 2.7.4, 3.0.2
  • bitnami ruby-min 2.6.8, 2.7.4, 3.0.2
  • oracle jd_edwards_enterpriseone_tools 9.2.6.1
  • jruby Debian 14, Debian 13, Debian 12 9.3.9.0+ds-1

debian advisories DEBIAN-CVE-2021-32066

  • ruby2.5 Ubuntu 18.04 LTS 2.5.1-1ubuntu1.10
  • ruby2.7 Ubuntu 20.04 LTS 2.7.0-5ubuntu1.5
  • ruby2.3 Ubuntu Pro 16.04 LTS 2.3.1-2~ubuntu16.04.16+esm1

ubuntu advisories UBUNTU-CVE-2021-32066

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

  • rubygem-pg RHEL 8, RHEL 8.4 EUS, RHEL 8.2 EUS +1 more 1.1.4-1.module+el8.1.0+3653+beb38eb0
  • rubygem-abrt RHEL 8, RHEL 8.4 EUS, RHEL 8.2 EUS +1 more 0.3.0-4.module+el8.1.0+3653+beb38eb0
  • rubygem-bson RHEL 8, RHEL 8.4 EUS, RHEL 8.2 EUS +1 more 4.5.0-1.module+el8.1.0+3653+beb38eb0
  • rubygem-mongo RHEL 8, RHEL 8.4 EUS, RHEL 8.2 EUS +1 more 2.8.0-1.module+el8.1.0+3653+beb38eb0
  • rh-ruby26-ruby RHEL 3 SOFTWARE_COLLECTIONS 2.6.9-120.el7
  • rh-ruby26-rubygems RHEL 3 SOFTWARE_COLLECTIONS 3.0.3.1-120.el7
  • rh-ruby26-ruby-libs RHEL 3 SOFTWARE_COLLECTIONS 2.6.9-120.el7
  • rh-ruby26-rubygem-irb RHEL 3 SOFTWARE_COLLECTIONS 1.0.0-120.el7

red hat advisories RHSA-2022:0582RHSA-2022:0581RHSA-2022:0708RHSA-2022:0672RHSA-2022:0544RHSA-2022:0543

  • ruby WebYast 1.3 1.8.7.p357-0.9.20.3.1
  • ruby2.5 SLES for SAP 15 SP2, SLES for SAP 15 SP1, SLES for SAP 15 +21 more 2.5.9-150000.4.23.1
  • ruby2.5 SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +10 more 2.5.9-4.20.1
  • ruby2.1 SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +11 more 2.1.9-19.6.1

suse advisories SUSE-SU-2022:15034-1SUSE-SU-2022:1512-1SUSE-SU-2021:3838-1SUSE-SU-2021:3837-1

  • ruby4.0 openSUSE Tumbleweed 4.0.0~preview2-1.1
  • ruby3.4 openSUSE Tumbleweed 3.4.1-1.1
  • ruby2.7 openSUSE Tumbleweed 2.7.4-1.1
  • ruby3.0 openSUSE Tumbleweed 3.0.2-1.1
  • ruby3.1 openSUSE Tumbleweed 3.1.0-1.1
  • ruby3.2 openSUSE Tumbleweed 3.2.1-1.1
  • ruby3.3 openSUSE Tumbleweed 3.3.0-1.2
  • ruby2.5 openSUSE Leap 15.2 2.5.9-lp152.2.9.1

opensuse advisories openSUSE-SU-2025:15819-1openSUSE-SU-2025:14621-1openSUSE-SU-2024:11622-1openSUSE-SU-2024:11623-1openSUSE-SU-2024:11786-1openSUSE-SU-2024:12712-1

  • ruby AlmaLinux 8 2.5.9-109.module_el8.5.0+2627+d9c243ca
  • ruby AlmaLinux 8 2.5.9-109.module_el8.5.0+259+8cec6917
  • ruby-irb AlmaLinux 8 2.5.9-109.module_el8.5.0+259+8cec6917
  • ruby-irb AlmaLinux 8 2.5.9-109.module_el8.5.0+2627+d9c243ca
  • rubygems AlmaLinux 8 2.7.6.3-109.module_el8.5.0+2627+d9c243ca
  • rubygems AlmaLinux 8 2.7.6.3-109.module_el8.5.0+259+8cec6917
  • ruby-libs AlmaLinux 8 2.5.9-109.module_el8.5.0+2627+d9c243ca
  • ruby-libs AlmaLinux 8 2.5.9-109.module_el8.5.0+259+8cec6917

almalinux advisories ALSA-2022:0672ALSA-2022:0543ALSA-2021:3020

  • ruby Rocky Linux 8 2.5.9-109.module+el8.5.0+740+b85cbe0d
  • rubygem-pg Rocky Linux 8 1.0.0-2.module+el8.4.0+592+03ff458a
  • rubygem-pg Rocky Linux 8 1.0.0-2.module+el8.3.0+167+5c390590
  • rubygem-abrt Rocky Linux 8 0.3.0-4.module+el8.5.0+738+032c9c02
  • rubygem-abrt Rocky Linux 8 0.3.0-4.module+el8.3.0+167+5c390590
  • rubygem-abrt Rocky Linux 8 0.3.0-4.module+el8.4.0+592+03ff458a
  • rubygem-bson Rocky Linux 8 4.3.0-2.module+el8.4.0+592+03ff458a
  • rubygem-bson Rocky Linux 8 4.3.0-2.module+el8.3.0+167+5c390590

rocky linux advisories RLSA-2022:0672RLSA-2022:0543RLSA-2021:3020

  • ruby Alpine 3.11 2.6.8-r0
  • ruby Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 2.7.4-r0

alpine advisories ALPINE-CVE-2021-32066

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

  • ruby CBL-Mariner 2.0 2.7.4-1

azure linux advisories AZL-6861

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • jruby Arch Linux 9.3.0.0-1
  • ruby Arch Linux 3.0.2-1

arch linux advisories AVG-1906AVG-2138

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-2021-32066 updated cvss 7.4

ruby: StartTLS stripping vulnerability in Net::IMAP

  • Red Hat Enterprise Linux 7 ruby, ruby-irb, rubygems, ruby-libs, ruby-tcltk, rubygem-json, +6 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) ruby 2.5.9-109.module+el8.5.0+14275+d9c243ca, ruby 2.6.9-108.module+el8.5.0+13719+08a8ba32, ruby 2.7.4-137.module+el8.4.0+12025+f744ca41, rubygem-pg 1.0.0-2.module+el8.1.0+3656+f80bfa1d, rubygem-pg 1.1.4-1.module+el8.1.0+3653+beb38eb0, rubygem-pg 1.2.3-1.module+el8.3.0+7192+4e3a532a, +63 more
    fixed: vendor fix RHSA-2021:3020
  • Red Hat Enterprise Linux AppStream E4S (v. 8.1) ruby 2.6.9-107.module+el8.1.0+14088+04cf326e, rubygem-pg 1.1.4-1.module+el8.1.0+3653+beb38eb0, ruby-libs 2.6.9-107.module+el8.1.0+14088+04cf326e, rubygem-abrt 0.3.0-4.module+el8.1.0+3653+beb38eb0, rubygem-bson 4.5.0-1.module+el8.1.0+3653+beb38eb0, rubygem-mongo 2.8.0-1.module+el8.1.0+3653+beb38eb0, +17 more
    fixed: vendor fix RHSA-2022:0581
  • Red Hat Enterprise Linux AppStream EUS (v. 8.2) ruby 2.6.9-107.module+el8.2.0+14086+86d863af, rubygem-pg 1.1.4-1.module+el8.1.0+3653+beb38eb0, ruby-libs 2.6.9-107.module+el8.2.0+14086+86d863af, rubygem-abrt 0.3.0-4.module+el8.1.0+3653+beb38eb0, rubygem-bson 4.5.0-1.module+el8.1.0+3653+beb38eb0, rubygem-mongo 2.8.0-1.module+el8.1.0+3653+beb38eb0, +17 more
    fixed: vendor fix RHSA-2022:0582
  • Red Hat Enterprise Linux AppStream EUS (v.8.4) ruby 2.6.9-108.module+el8.4.0+14070+b3717926, rubygem-pg 1.1.4-1.module+el8.1.0+3653+beb38eb0, ruby-libs 2.6.9-108.module+el8.4.0+14070+b3717926, rubygem-abrt 0.3.0-4.module+el8.1.0+3653+beb38eb0, rubygem-bson 4.5.0-1.module+el8.1.0+3653+beb38eb0, rubygem-mongo 2.8.0-1.module+el8.1.0+3653+beb38eb0, +17 more
    fixed: vendor fix RHSA-2022:0544
  • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) rh-ruby27-ruby 2.7.4-130.el7, rh-ruby30-ruby 3.0.2-148.el7, rh-ruby27-rubygems 3.1.6-130.el7, rh-ruby27-ruby-libs 2.7.4-130.el7, rh-ruby30-ruby-libs 3.0.2-148.el7, rh-ruby30-rubygems 3.2.22-148.el7, +31 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7) rh-ruby27-ruby 2.7.4-130.el7, rh-ruby30-ruby 3.0.2-148.el7, rh-ruby27-rubygems 3.1.6-130.el7, rh-ruby27-ruby-libs 2.7.4-130.el7, rh-ruby30-ruby-libs 3.0.2-148.el7, rh-ruby30-rubygems 3.2.22-148.el7, +31 more Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) rh-ruby27-ruby 2.7.4-130.el7, rh-ruby30-ruby 3.0.2-148.el7, rh-ruby27-rubygems 3.1.6-130.el7, rh-ruby27-ruby-libs 2.7.4-130.el7, rh-ruby30-ruby-libs 3.0.2-148.el7, rh-ruby30-rubygems 3.2.22-148.el7, +31 more
    fixed: vendor fix RHSA-2021:3559
  • Red Hat Software Collections for RHEL Workstation(v. 7) rh-ruby26-ruby 2.6.9-120.el7, rh-ruby26-ruby-libs 2.6.9-120.el7, rh-ruby26-rubygems 3.0.3.1-120.el7, rh-ruby26-rubygem-irb 1.0.0-120.el7, rh-ruby26-rubygem-json 2.1.0-120.el7, rh-ruby26-rubygem-psych 3.1.0-120.el7, +12 more Red Hat Software Collections for RHEL(v. 7) rh-ruby26-ruby 2.6.9-120.el7, rh-ruby26-ruby-libs 2.6.9-120.el7, rh-ruby26-rubygems 3.0.3.1-120.el7, rh-ruby26-rubygem-irb 1.0.0-120.el7, rh-ruby26-rubygem-json 2.1.0-120.el7, rh-ruby26-rubygem-psych 3.1.0-120.el7, +12 more
    fixed: vendor fix RHSA-2022:0708
  • Red Hat Enterprise Linux 6 ruby, ruby-ri, ruby-irb, ruby-libs, ruby-rdoc, ruby-tcltk Red Hat Enterprise Linux 9 ruby, rubygems, ruby-libs, rubygem-irb, rubygem-rbs, rubygem-rss, +13 more
    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

Exploit prediction

2.91% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/1178562 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N
OSV 3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
bitnami ruby
>=2.6.0, <2.6.8
>=2.7.0, <2.7.4
>=3.0.0, <3.0.2
2.6.8
2.7.4
3.0.2
bitnami ruby-min
>=2.6.0, <2.6.8
>=2.7.0, <2.7.4
>=3.0.0, <3.0.2
2.6.8
2.7.4
3.0.2
julia ruby_jll
all versions
 no fix listed

Classification

Weakness
  • CWE-755 Improper Handling of Exceptional Conditions

References

Sources

Fencer Vulns 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.