---
id: "CVE-2026-122054"
kind: "vulnerability"
aliases: ["CVE-2026-122054"]
title: "GNU C Library: crafted BIG-HKSCS input makes iconv hang"
severity: "medium"
cvss: 5.9
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["glibc", "iconv", "infrastructure", "linux"]
not_affected_if: ["default-config", "no-untrusted-input"]
published_at: "2026-11-04T18:17:43+00:00"
first_seen_at: "2026-11-04T18:28:34+00:00"
updated_at: "2026-11-04T18:29:41+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-122054", "first_seen_at": "2026-11-04T18:28:34+00:00"}]
---

# GNU C Library: crafted BIG-HKSCS input makes iconv hang

Converting specially crafted BIG-HKSCS text to UCS-4 or the internal wide character encoding with iconv in glibc 2.18 through 2.31 can make the converter stop making progress. The calling application then hangs.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the glibc version with `ldd --version`, and see whether it falls in the affected range 2.18 through 2.31.
- Look for programs that convert untrusted input from BIG-HKSCS with iconv or iconv_open.

## Timeline

- 2026-11-04T18:28:34+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-122054

## From the sources

Converting crafted BIG-HKSCS input to UCS-4 or the internal wide character encoding, for example with iconv, in the GNU C Library version 2.18 through 2.31 may result in the converter making no progress, causing the calling application to hang.

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