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Fencer Vulns
low 2.1

CVE-2026-47241 json

Net::IMAP: Denial of Service via incomplete raw argument validation

published 2026-06-09 5 mo ago modified 2026-10-25 14 d ago also EUVD-2026-38350 , GHSA-c4fp-cxrr-mj66

cvss
2.1
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits
0
none known

Summary

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, several Net::IMAP commands accept a raw string argument which is only validated to prevent CRLF injection and then sent verbatim. If this string is derived from user-controlled input, an attacker can force the next command to be absorbed as a continuation of the first command. This will cause the first command to eventually fail, but also prevents it from returning until another command is sent (from another thread). That other command will not return until the connection is closed. This vulnerability is fixed in 0.6.5 and 0.5.15.

Patch / fix

  • rubygems net-imap 0.5.15, 0.6.4.1
  • ruby-lang net-imap 0.5.15, 0.6.4.1
  • ruby-lang net::imap 0.5.15, 0.6.4.1
  • ruby3.3 Debian 13 3.3.13-0+deb13u1

debian advisories DEBIAN-CVE-2026-47241

  • ruby RHEL 9 3.3.12-8.module+el9.8.0+24568+2bbebe96
  • rubygems RHEL 9 3.5.22-8.module+el9.8.0+24568+2bbebe96
  • ruby-libs RHEL 9 3.3.12-8.module+el9.8.0+24568+2bbebe96
  • rubygem-pg RHEL 9 1.5.4-2.module+el9.8.0+24356+77305e91
  • rubygem-irb RHEL 9 1.13.1-8.module+el9.8.0+24568+2bbebe96
  • rubygem-rbs RHEL 9 3.4.0-8.module+el9.8.0+24568+2bbebe96
  • rubygem-rss RHEL 9 0.3.1-8.module+el9.8.0+24568+2bbebe96
  • rubygem-json RHEL 9 2.7.2-8.module+el9.8.0+24568+2bbebe96

red hat advisories RHSA-2026:50828RHSA-2026:50827RHSA-2026:50778RHSA-2026:50773RHSA-2026:50728RHSA-2026:40380

  • ruby3.4 SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 3.4.10-150700.3.4.1

suse advisories SUSE-SU-2026:3090-1

  • ruby3.4 openSUSE Leap 16.0 3.4.10-160000.1.1

opensuse advisories openSUSE-SU-2026:21878-1

  • ruby AlmaLinux 8 3.3.12-8.module_el8.10.0+4241+4264e34b
  • rubygems AlmaLinux 8 3.5.22-8.module_el8.10.0+4241+4264e34b
  • ruby-libs AlmaLinux 8 3.3.12-8.module_el8.10.0+4241+4264e34b
  • rubygem-pg AlmaLinux 8 1.5.4-1.module_el8.10.0+3799+191214cc
  • rubygem-irb AlmaLinux 8 1.13.1-8.module_el8.10.0+4241+4264e34b
  • rubygem-rbs AlmaLinux 8 3.4.0-8.module_el8.10.0+4241+4264e34b
  • rubygem-rss AlmaLinux 8 0.3.1-8.module_el8.10.0+4241+4264e34b
  • rubygem-abrt AlmaLinux 8 0.4.0-1.module_el8.10.0+3799+191214cc

almalinux advisories ALSA-2026:50728ALSA-2026:50773ALSA-2026:50778ALSA-2026:50827ALSA-2026:50828

  • ruby4.0 Rocky Linux 10 4.0.6-36.el10_2
  • ruby Rocky Linux 10 3.3.12-14.el10_2
  • ruby Rocky Linux 9 4.0.6-34.module+el9.8.0+40271+b5850c84
  • rubygem-pg Rocky Linux 9 1.6.3-1.module+el9.8.0+40094+ce01217c
  • rubygem-mysql2 Rocky Linux 9 0.5.7-1.module+el9.8.0+40094+ce01217c
  • ruby Rocky Linux 9 3.3.12-8.module+el9.8.0+40270+7a73441e
  • rubygem-pg Rocky Linux 9 1.5.4-2.module+el9.7.0+40188+314ad260.0.1
  • rubygem-mysql2 Rocky Linux 9 0.5.5-3.module+el9.7.0+40032+36e56d0d

rocky linux advisories RLSA-2026:50773RLSA-2026:50778RLSA-2026:50827RLSA-2026:50828RLSA-2026:50728

  • ruby-net-imap Alpine 3.21 0.4.25-r0
  • ruby-net-imap Alpine 3.24, Alpine 3.23, Alpine 3.22 0.5.15-r0

alpine advisories ALPINE-CVE-2026-47241

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

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-2026-47241 updated cvss 5.9

net-imap: rubygem-net-imap: Net::IMAP: Denial of Service via malformed command input

  • Red Hat Enterprise Linux AppStream (v. 8) ruby 3.3.12-8.module+el8.10.0+24567+c4e5368e, rubygems 3.5.22-8.module+el8.10.0+24567+c4e5368e, ruby-libs 3.3.12-8.module+el8.10.0+24567+c4e5368e, rubygem-pg 1.5.4-1.module+el8.10.0+21226+b78a28c4, rubygem-rbs 3.4.0-8.module+el8.10.0+24567+c4e5368e, rubygem-rss 0.3.1-8.module+el8.10.0+24567+c4e5368e, +18 more
    fixed: vendor fix RHSA-2026:50728
  • Red Hat Enterprise Linux AppStream (v. 9) ruby 3.3.12-8.module+el9.8.0+24568+2bbebe96, ruby 4.0.6-34.module+el9.8.0+24564+e55418dc, rubygems 3.5.22-8.module+el9.8.0+24568+2bbebe96, ruby-libs 3.3.12-8.module+el9.8.0+24568+2bbebe96, ruby-libs 4.0.6-34.module+el9.8.0+24564+e55418dc, rubygem-pg 1.5.4-2.module+el9.8.0+24356+77305e91, +40 more
    fixed: vendor fix RHSA-2026:50828
  • Red Hat Enterprise Linux AppStream (v. 10) ruby 3.3.12-14.el10_2, ruby4.0 4.0.6-36.el10_2, rubygems 3.5.22-14.el10_2, ruby-libs 3.3.12-14.el10_2, rubygem-rbs 3.4.0-14.el10_2, rubygem-rss 0.3.1-14.el10_2, +18 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) ruby-doc 3.3.12-14.el10_2, ruby4.0-doc 4.0.6-36.el10_2
    fixed: vendor fix RHSA-2026:50778
  • Red Hat Hardened Images ruby3.4 3.4.8-31.3.hum1, ruby4.0 4.0.0-33.4.hum1, ruby3.3 3.3.10-23.4.hum1, ruby3.4-libs 3.4.8-31.3.hum1, ruby4.0-libs 4.0.0-33.4.hum1, ruby3.3-libs 3.3.10-23.4.hum1, +23 more
    fixed: vendor fix RHSA-2026:40380
  • Red Hat 3scale API Management Platform 2 3scale-amp21/zync, 3scale-amp22/zync, 3scale-amp21/system, 3scale-amp22/system, 3scale-amp2/zync-rhel8, 3scale-amp2/zync-rhel9, +3 more Red Hat Hardened Images rubygem3.4-rbs 3.8.0-31.3.hum1, rubygem3.4-rss 0.3.1-31.3.hum1, rubygem4.0-rss 0.3.2-33.4.hum1, rubygem3.4-irb 1.14.3-31.3.hum1, rubygem3.4-json 2.9.1-31.3.hum1, rubygem3.4-racc 1.8.1-31.3.hum1, +28 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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 2.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CNA 4.0 2.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
rubygems net-imap
>=0.6.0, <0.6.4.1
<0.5.15
0.6.4.1
0.5.15

Affected products

  • ruby net-imap

Classification

Weakness
  • CWE-162 Improper Neutralization of Trailing Special Elements
  • CWE-182 Collapse of Data into Unsafe Value
  • CWE-186 Overly Restrictive Regular Expression

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.