EUC_JISX0213 decoding may hang on crafted input (CVE-2026-80489)

What is affected, what to do

A flaw was found in glibc. Converting crafted EUC_JISX0213 input to UCS-4 or the internal wide character encoding (for example with iconv) can cause the converter to make no progress, hanging the calling application.

The available sources name no fixed version. Check the vendor guidance in the references below.

Affected

• The GNU C Library Glibc lte 2.3..2.44

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Metrics

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2

NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

Read in glossary

Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.

CRA

The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

Read in glossary

From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.

ISO/IEC 27001

ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

Read in glossary

Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

A flaw was found in glibc. Converting crafted EUC_JISX0213 input to UCS-4 or the internal wide character encoding (for example with iconv) can cause the converter to make no progress, hanging the calling application. Some EUC_JISX0213 sequences decode to two code points; if the output buffer has room for only the first, the second is stored in conversion state and returned as E2BIG, but that pending character is never cleared after it is emitted on the next call, so retries loop forever without consuming further input.

Source: redhat_csaf, BSI WID Portal, BSI CSAF, suse_csaf, cvelistv5, NVD (NIST), CVE.org (MITRE), Ubuntu Security Notices, Microsoft Security Update Guide

Vendors and products

• The Gnu C Library Glibc
• Ubuntu Glibc

Weakness classes (CWE)

• CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')

  Base

  The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

  Entry at MITRE CWE-835

References & sources

• sourceware.orgbugzilla/show_bug.cgi?id=34568Issue tracking
• sourceware.orggit/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0020Vendor advisory

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

1. 15.09.2026Record modifiedCISA ADP

   CISA assessment (SSVC): exploitation: none known, automatable: no

   Show the original change

   Individual changes of this event as published by NVD

   Type	Action	Before	After
   SSVC assessment	added	—	{"id":"CVE-2026-80489","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-09-15T12:21:33.409321Z"}

   Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

2. 15.09.2026Received3ff69d7a…

   CVSS V3.1: AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

   Weakness type: CWE-835

   Description added or changed

   New references:

   • https://sourceware.org/bugzilla/show_bug.cgi?id=34568
   • https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0020
   Show 6 original changes

   Individual changes of this event as published by NVD

   Type	Action	Before	After
   Description	added	—	Converting crafted EUC_JISX0213 input to UCS-4 or the internal wide character encoding, for example with iconv, in the GNU C Library version 2.3 to 2.44 may result in the converter making no progress, causing the calling application to hang. Some EUC_JISX0213 sequences decode to two code points. If the output buffer has room for only the first one, the converter stores the second in the conversion state and returns E2BIG, but it never clears that pending character after emitting it on the next call. The converter then keeps emitting the pending character without consuming further input, so an application that retries the conversion loops forever. The input must be attacker controlled and the application must convert it with an output buffer small enough to split the two code points. Only the EUC_JISX0213 character set is affected, which is not commonly used. The related defect in SHIFT_JISX0213 converter is tracked separately as CVE-2026-77117.
   CVSS	added	—	AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
   Weakness type (CWE)	added	—	CWE-835
   Affected versions (publisher)	added	—	New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/80xxx/CVE-2026-80489.json">CVE-2026-80489</a>
   Reference	added	—	https://sourceware.org/bugzilla/show_bug.cgi?id=34568
   Reference	added	—	https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0020

   Source identifier: 3ff69d7a-14f2-4f67-a097-88dee7810d18