CVE catalog
CVE-2026-42257
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, several Net::IMAP commands accept a raw string argument that is
- Severity
- Critical · CVSS 9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.43% · Oct 25, 2026
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, several Net::IMAP commands accept a raw string argument that is sent to the server without validation or escaping. If this string is derived from user-controlled input, it may contain contain CRLF sequences, which an attacker can use to inject arbitrary IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | ruby3.1 | bookworm | 3.1.2-7+deb12u1 | vulnerable |
| Debian | ruby3.1 | bookworm-security | 3.1.2-7+deb12u1 | vulnerable |
| Cpe | ruby3.2 | Not reported | 3.2.3-1ubuntu0.24.04.8 | fixed |
| Cpe | libruby3.2 | Not reported | 3.2.3-1ubuntu0.24.04.8 | fixed |
| Cpe | ruby3.2-dev | Not reported | 3.2.3-1ubuntu0.24.04.8 | fixed |
| Cpe | ruby3.2-doc | Not reported | 3.2.3-1ubuntu0.24.04.8 | fixed |
| Cpe | ruby3.1 | Not reported | Not reported | vulnerable |
| Cpe | net\ | Not reported | 0.4.24 | fixed |
| Cpe | net\ | Not reported | 0.5.14 | fixed |
| Cpe | net\ | Not reported | 0.6.4 | fixed |
| Alpine | ruby-net-imap | 3.21 | 0.4.25-r0 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | ruby3.1 | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Cpe | ruby3.2 | cpe | Not reported | 3.2.3-1ubuntu0.24.04.8 | Not reported | Not reported | Not reported |
| Cpe | libruby3.2 | cpe | Not reported | 3.2.3-1ubuntu0.24.04.8 | Not reported | Not reported | Not reported |
| Cpe | ruby3.2-dev | cpe | Not reported | 3.2.3-1ubuntu0.24.04.8 | Not reported | Not reported | Not reported |
| Cpe | ruby3.2-doc | cpe | Not reported | 3.2.3-1ubuntu0.24.04.8 | Not reported | Not reported | Not reported |
| Cpe | net\ | cpe | Not reported | 0.4.24 | Not reported | Not reported | Not reported |
| Cpe | net\ | cpe | Not reported | 0.5.14 | Not reported | Not reported | Not reported |
| Cpe | net\ | cpe | Not reported | 0.6.4 | Not reported | Not reported | Not reported |
| Alpine | ruby-net-imap | apk | 3.21 | 0.4.25-r0 | Not reported | ALPINE-CVE-2026-42257 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libruby3.1]Affected
Source package: [ruby3.1]
Details (4)
3.1.2-7+deb12u1· amd64 · bookwormAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· arm64 · bookwormAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· amd64 · bookworm-securityAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· arm64 · bookworm-securityAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
- [ruby3.1]Affected
Details (4)
3.1.2-7+deb12u1· amd64 · bookwormAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· arm64 · bookwormAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· amd64 · bookworm-securityAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· arm64 · bookworm-securityAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
- [ruby3.1-dev]Affected
Source package: [ruby3.1]
Details (4)
3.1.2-7+deb12u1· amd64 · bookwormAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· arm64 · bookwormAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· amd64 · bookworm-securityAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· arm64 · bookworm-securityAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
- [ruby3.1-doc]Affected
Source package: [ruby3.1]
Details (4)
3.1.2-7+deb12u1· all · bookwormAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· all · bookwormAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· all · bookworm-securityAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
3.1.2-7+deb12u1· all · bookworm-securityAffected
nvd · ruby3.1 · debian · bookworm; nvd · ruby3.1 · debian · 12
[Debian 13 (Trixie)]
- [libruby3.3]Affected
Source package: [ruby3.3]
Details (2)
3.3.8-2· amd64 · trixieAffected
nvd · ruby3.3 · debian · 13
3.3.8-2· arm64 · trixieAffected
nvd · ruby3.3 · debian · 13
- [ruby3.3]Affected
Details (2)
3.3.8-2· amd64 · trixieAffected
nvd · ruby3.3 · debian · 13
3.3.8-2· arm64 · trixieAffected
nvd · ruby3.3 · debian · 13
- [ruby3.3-dev]Affected
Source package: [ruby3.3]
Details (2)
3.3.8-2· amd64 · trixieAffected
nvd · ruby3.3 · debian · 13
3.3.8-2· arm64 · trixieAffected
nvd · ruby3.3 · debian · 13
- [ruby3.3-doc]Affected
Source package: [ruby3.3]
Details (2)
3.3.8-2· all · trixieAffected
nvd · ruby3.3 · debian · 13
3.3.8-2· all · trixieAffected
nvd · ruby3.3 · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/rhsa-2026_50728.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-42257]
- [https://osv.dev/vulnerability/ALPINE-CVE-2026-42257]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-42257]
- [https://security-tracker.debian.org/tracker/CVE-2026-42257]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42257.json]
- [https://ubuntu.com/security/notices/USN-8478-1]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2117.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]