Medium severity · published May 9, 2026
CVE-2026-42258
net-imap: Command Injection via unvalidated Symbol inputs
5.3
CVSS
0.8%
EPSS
No
On KEV
Description
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, symbol arguments to commands are vulnerable to a CRLF Injection / IMAP Command injection via Symbol arguments passed to IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L
Attack vector
Local
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
High
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.8% · higher than 56% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NE
net-imap · ruby
< 0.4.24; >= 0.5.0, < 0.5.14; >= 0.6.0, < 0.6.4 · source: vendor
NE
Net::imap · Ruby-lang
before 0.4.24; 0.5.0 before 0.5.14; 0.6.0 before 0.6.4 · source: NVD
RH
Red Hat 3scale API Management Platform 2 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 10.0 Extended Update Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 7 Extended Lifecycle Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.8 Telecommunications Update Service · Red Hat
All versions, or not specified · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42258
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-42258
Release Notes
https://github.com/ruby/net-imap/releases/tag/v0.4.24
Release Notes
https://github.com/ruby/net-imap/releases/tag/v0.5.14
Release Notes
https://github.com/ruby/net-imap/releases/tag/v0.6.4
Mitigation
https://github.com/ruby/net-imap/security/advisories/GHSA-75xq-5h9v-w6px
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:33462
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:33512
More from net-imap
9.8
CVE-2026-42257
net-imap: Command Injection via "raw" arguments to multiple commands
7.5
CVE-2026-42245
net-imap: Quadratic complexity when reading response literals
7.4
CVE-2026-42246
net-imap vulnerable to STARTTLS stripping via invalid response timing
6.5
CVE-2026-42256
net-imap: Denial of service via high iteration count for `SCRAM-*` authentication
5.8
CVE-2026-47242
Net::IMAP: Command Injection via ID command argument