CVE catalog
CVE-2026-42256
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. From versions 0.4.0 to before 0.4.24, 0.5.0 to before 0.5.14, and 0.6.0 to before 0.6.4, when authenticating
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.30% · Oct 25, 2026
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. From versions 0.4.0 to before 0.4.24, 0.5.0 to before 0.5.14, and 0.6.0 to before 0.6.4, when authenticating a connection with SCRAM-SHA1 or SCRAM-SHA256, a hostile server can perform a computational denial-of-service attack on the client process by sending a big iteration count value. 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 |
| Suse | rmt-server | linux enterprise module for public cloud 15 sp7 | 3.1.0-150700.3.28.1 | fixed |
| Suse | rmt-server | linux enterprise module for server applications 15 sp7 | 3.1.0-150700.3.28.1 | fixed |
| Opensuse | rmt-server | leap 16.0 | 3.0.0-160000.1.1 | 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 |
| Suse | rmt-server | rpm | linux enterprise module for public cloud 15 sp7 | 3.1.0-150700.3.28.1 | Not reported | SUSE-SU-2026:3792-1 | Not reported |
| Suse | rmt-server | rpm | linux enterprise module for server applications 15 sp7 | 3.1.0-150700.3.28.1 | Not reported | SUSE-SU-2026:3792-1 | Not reported |
| Opensuse | rmt-server | rpm | leap 16.0 | 3.0.0-160000.1.1 | Not reported | OPENSUSE-SU-2026:21225-1 | Not reported |
| Alpine | ruby-net-imap | apk | 3.21 | 0.4.25-r0 | Not reported | ALPINE-CVE-2026-42256 | 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/opensuse-su-2026_21225-1.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-42256]
- [https://osv.dev/vulnerability/ALPINE-CVE-2026-42256]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-42256]
- [https://osv.dev/vulnerability/SUSE-SU-2026:3792-1]
- [https://osv.dev/vulnerability/openSUSE-SU-2026:21225-1]
- [https://security-tracker.debian.org/tracker/CVE-2026-42256]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42256.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)]