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No exploitation reportedFix available

CVE-2021-43396

No exploitation reported by the sources we read.

  • Published2021-11-04

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

In iconvdata/iso-2022-jp-3.c in the GNU C Library (aka glibc) 2.34, remote attackers can force iconv() to emit a spurious '\0' character via crafted ISO-2022-JP-3 data that is accompanied by an internal state reset. This may affect data integrity in certain iconv() use cases. NOTE: the vendor states "the bug cannot be invoked through user input and requires iconv to be invoked with a NULL inbuf, which ought to require a separate application bug to do so unintentionally. Hence there's no security impact to the bug.

Timeline

dates in UTC
  1. 2021-11-0420:15CVE publishedNVD

Versions per branch

NVD
Oracle enterprise operations monitor
BranchAffectedFixed in
4.3= 4.3no fix published
4.4= 4.4no fix published
5.0= 5.0no fix published
Oracle communications cloud native core network repository function
BranchAffectedFixed in
22.1= 22.1.2no fix published
22.2= 22.2.0no fix published
Gnu glibc
BranchAffectedFixed in
2.34= 2.34no fix published

4 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • glibcTuxCare:OracleLinux:6all versions · fixed in 2.12-2.215.el6.cloudlinux.elsand 6 other packages
  • glibcTuxCare:CentOS:6all versions · fixed in 2.12-2.215.el6.cloudlinux.elsand 6 other packages
  • glibcopenEuler:20.03-LTS-SP2all versions · fixed in 2.28-79.oe1
  • glibcopenEuler:20.03-LTS-SP1all versions · fixed in 2.28-79.oe1
  • glibcDebian:14all versions · fixed in 2.32-5
  • glibcDebian:13all versions · fixed in 2.32-5
  • glibcDebian:12all versions · fixed in 2.32-5
  • glibcAzure Linux:2all versions · fixed in 2.35-1

2 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-43396 Red Hat Product Security

    glibc: conversion from ISO-2022-JP-3 with iconv may emit spurious NUL character on state reset

  • ICSA-23-348-10 CISA5 known affected

    Siemens SIMATIC S7-1500

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) · +2 more

  • SSA-398330 Siemens ProductCERT5 known affected

    SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.0 < V3.1.5 · +2 more

Full record on NVD

Fix

  1. Vendor fix CISA ICSA-23-348-10 · 5 productsUpdate to V3.1.5 or later version
  2. Vendor fix Siemens ProductCERT SSA-398330 · 1 productUpdate to V3.1.5 or later version
  3. Mitigation from the vendor CISA ICSA-23-348-10 · 5 productsOnly build and run applications from trusted sources.

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Published
2021-11-04
Last Modified
2026-10-14
NVD status
Modified
GitHub Advisory
GHSA-73g2-m4v3-6c2h

Frequently asked questions

What is CVE-2021-43396?

In iconvdata/iso-2022-jp-3.c in the GNU C Library (aka glibc) 2.34, remote attackers can force iconv() to emit a spurious '\0' character via crafted ISO-2022-JP-3 data that is accompanied by an internal state reset. This may affect data integrity in certain iconv() use cases. NOTE: the vendor states "the bug cannot be invoked through user input and requires iconv to be invoked with a NULL inbuf, which ought to require a separate application bug to do so unintentionally. Hence there's no security impact to the bug.

Is CVE-2021-43396 actively exploited?

Active exploitation of CVE-2021-43396 has not been confirmed. Its EPSS score was 3.3% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-43396?

CVE-2021-43396 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

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