CVE-2026-42246
Ruby-Lang Net\ \
Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/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:XSummary
CVE-2026-42246 is a high-severity Missing Report of Error Condition (CWE-392) vulnerability in Ruby-Lang Net\. Its CVSS base score is 7.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Service Stop (T1489); ranked at the 24th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to CP-12 (Safe Mode) and SA-11 (Developer Testing and Evaluation) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-28924
Vulnerability Data
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10, 0.4.24,…
more
0.5.14, and 0.6.4.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 21 hardening rules · 6 OS baselines
V3.2.1V7.4.1V8.3.3V10.3.4
Mitigating Controls (NIST 800-53 r5) AI
Requires selection and implementation of specific approved cryptographic algorithms and methods, reducing the chance that an incomplete algorithm is used.
SC-24 directly requires the system to fail to a known state that preserves security properties, structurally stopping fallback to a less-secure mode.
SI-17 mandates explicit fail-safe procedures that activate on indicated failures, preventing the insecure fallback behavior.
CP-12 forces entry into a safe mode on detected conditions, limiting exposure but not covering every failure path.
Developer testing and evaluation at post-design stages directly exercises code paths and can identify functions returning incorrect status codes.
Input validation directly requires checking for unexpected or malformed conditions before they propagate.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Requiring log generation directly forces error conditions to be reported so they become visible to monitoring.
Secure SDLC practices include explicit coding standards for reporting all error conditions.
Runtime monitoring can surface unreported errors only if the underlying code already emits them.
Least-privilege policy and enforcement directly counters the permissive-access fallback example in the CWE.
Proper encryption of data-at-rest requires all algorithm steps; omitting one directly weakens the control.
Proper encryption of data-in-transit requires all algorithm steps; omitting one directly weakens the control.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can identify missing error reporting through negative test cases and exception handling checks.
Logging of errors and exceptions helps ensure that error conditions are captured and reported.
Monitoring activities can detect missing error reporting by observing abnormal system behavior.
Mandates correct use of cryptographic controls, directly preventing omission of required algorithm steps.
Secure development lifecycle practices include requirements for proper error handling and status reporting.
Application security requirements typically mandate explicit error condition reporting to calling components.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (4 rules)
- V-248524 OL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
- V-248535 The OL 8 shadow password suite must be configured to use a sufficient number of hashing rounds. prevents CWE-325
- V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-754
Oracle Linux 9 (2 rules)
- V-271454 OL 9 must enable FIPS mode. prevents CWE-325
- V-271452 OL 9 must use a Linux Security Module configured to enforce limits on system services. prevents CWE-754
RHEL 7 (1 rule)
- V-204497 The Red Hat Enterprise Linux operating system must implement NIST FIPS-validated cryptography for the following: to provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
RHEL 8 (1 rule)
- V-230223 RHEL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
Ubuntu 22.04 (1 rule)
- V-260650 Ubuntu 22.04 LTS must implement NIST FIPS-validated cryptography to protect classified information and for the following: To provision digital signatures, to generate cryptographic hashes, and to protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325
Ubuntu 24.04 (1 rule)
- V-270744 Ubuntu 24.04 LTS must implement NIST FIPS-validated cryptography to protect classified information and for the following: To provision digital signatures, to generate cryptographic hashes, and to protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-325