CVE-2026-4046
Gnu Glibc ≤ 2.43
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-4046 is a high-severity Reachable Assertion (CWE-617) vulnerability in Gnu Glibc. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 31th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-4046 affects the iconv() function in the GNU C Library (glibc) versions 2.43 and earlier. The vulnerability causes an assertion failure and subsequent crash when processing inputs from the IBM1390 or IBM1399 character sets, potentially leading to denial-of-service in applications that invoke iconv() for character conversion.
Attackers can exploit this remotely over the network with low complexity, requiring no privileges or user interaction, as indicated by the CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). Any unauthenticated remote attacker can supply malicious input to vulnerable applications using these character sets, achieving application crashes and high availability impact without affecting confidentiality or integrity.
Advisories recommend trivial mitigation by removing the IBM1390 and IBM1399 character sets from systems that do not require them, as detailed in the glibc security advisory (GLIBC-SA-2026-0007) and related Sourceware bugzilla entry. References include the libc-announce mailing list, bugzilla #33980, and the glibc git advisory blob.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17144
Vulnerability Data
The iconv() function in the GNU C Library versions 2.43 and earlier may crash due to an assertion failure when converting inputs from the IBM1390 or IBM1399 character sets, which may be used to remotely crash an application. This vulnerability…
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can be trivially mitigated by removing the IBM1390 and IBM1399 character sets from systems that do not need them.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation finds reachable assertions during development.
Security engineering principles discourage use of assertions for handling untrusted input.
Validating untrusted inputs structurally prevents attacker data from reaching and triggering assertions.
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.
Secure SDLC practices directly prevent unsafe assertions from being coded in reachable paths.
Runtime monitoring of software can detect assertion-triggered crashes as adverse events.
Vulnerability identification processes can discover and record reachable-assertion flaws before deployment.
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 in development can detect reachable assertions before release, reducing the likelihood of exploitation.
Secure development lifecycle mandates defensive coding and input validation that prevent reachable assertions from being triggered by untrusted data.
Application security requirements can specify that assertions must not be reachable from attacker-controlled inputs.
Secure architecture principles discourage the use of assertions for runtime error handling that an attacker could exploit.
Secure coding standards explicitly ban the use of assert() or equivalent statements that can be triggered by external input.