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Fencer Vulns
high 7.5

CVE-2026-4046 json

iconv crash due to assertion failure with untrusted input

published 2026-03-30 7 mo ago modified 2026-10-15 25 d ago also EUVD-2026-17144

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits
0
none known

Summary

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.

Patch / fix

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.6
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.6
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.6
  • glibc Debian 12 2.36-9+deb12u14
  • glibc Debian 13 2.41-12+deb13u3
  • glibc Debian 14 2.42-15

debian advisories DEBIAN-CVE-2026-4046

  • glibc Ubuntu 22.04 LTS 2.35-0ubuntu3.14
  • glibc Ubuntu 24.04 LTS 2.39-0ubuntu8.8
  • glibc Ubuntu 26.04 LTS 2.43-2ubuntu2.3

ubuntu advisories UBUNTU-CVE-2026-4046

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • glibc RHEL 9 2.34-270.el9_8
  • nscd RHEL 9 2.34-270.el9_8
  • libnsl RHEL 9 2.34-270.el9_8
  • nss_db RHEL 9 2.34-270.el9_8
  • nss_hesiod RHEL 9 2.34-270.el9_8
  • glibc-utils RHEL 9 2.34-270.el9_8
  • glibc-common RHEL 9 2.34-270.el9_8
  • glibc-benchtests RHEL 9 2.34-270.el9_8

red hat advisories RHSA-2026:20597RHSA-2026:20594RHSA-2026:20587RHSA-2026:12740

  • glibc SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +8 more 2.31-150300.101.1
  • glibc Linux Micro Extras 6.2 2.40-160000.5.1
  • glibc SLES 11 SP4 LTSS EXTREME CORE 2.11.3-17.110.55.1
  • glibc SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.22-114.46.1
  • glibc-livepatches SLE Live Patching 15 SP7 0.4-150700.10.7.1
  • glibc-livepatches SLE Live Patching 15 SP6 0.4-150600.8.5.1

suse advisories SUSE-SU-2026:2465-1SUSE-SU-2026:2440-1SUSE-SU-2026:2333-1SUSE-SU-2026:21780-1SUSE-SU-2026:1501-1SUSE-SU-2026:1498-1

  • glibc openSUSE Tumbleweed 2.43-2.1

opensuse advisories openSUSE-SU-2026:10722-1

  • glibc AlmaLinux 8 2.28-251.el8_10.37
  • nscd AlmaLinux 8 2.28-251.el8_10.37
  • libnsl AlmaLinux 8 2.28-251.el8_10.37
  • nss_db AlmaLinux 8 2.28-251.el8_10.37
  • nss_hesiod AlmaLinux 8 2.28-251.el8_10.37
  • glibc-utils AlmaLinux 8 2.28-251.el8_10.37
  • glibc-common AlmaLinux 8 2.28-251.el8_10.37
  • glibc-benchtests AlmaLinux 8 2.28-251.el8_10.37

almalinux advisories ALSA-2026:20587ALSA-2026:20594ALSA-2026:20597

  • glibc Rocky Linux 10 2.39-124.el10_2
  • glibc Rocky Linux 9 2.34-270.el9_8
  • glibc Rocky Linux 8 2.28-251.el8_10.37

rocky linux advisories RLSA-2026:20594RLSA-2026:20597RLSA-2026:20587

  • glibc Azure Linux 3.0 2.38-20

azure linux advisories AZL-81273

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-4046 updated cvss 5.3

glibc: glibc: Denial of Service via iconv() function with specific character sets

  • Red Hat Enterprise Linux 6 nscd, glibc, glibc-utils, compat-glibc, glibc-common Red Hat Enterprise Linux 7 nscd, glibc, glibc-utils, compat-glibc, glibc-common
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift Container Platform 4 openshift4/ose-hypershift-rhel9
    under investigation
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.17 cert-manager/cert-manager-operator-rhel9 1791788287, cert-manager/jetstack-cert-manager-rhel9 1791371069, cert-manager/cert-manager-operator-bundle 1791970484, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791371080
    fixed: vendor fix RHSA-2026:82888
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.18 cert-manager/cert-manager-operator-rhel9 1789029076, cert-manager/jetstack-cert-manager-rhel9 1791459711, cert-manager/cert-manager-istio-csr-rhel9 1791459759, cert-manager/cert-manager-operator-bundle 1791966259, cert-manager/jetstack-cert-manager-acmesolver-rhel9 1791459707
    fixed: vendor fix RHSA-2026:82354
  • Red Hat Cert Manager support for Red Hat OpenShift release 1.20 cert-manager/cert-manager-trust-manager-rhel9 1790598593
    fixed: vendor fix RHSA-2026:72502
  • Red Hat Cost Management 4 costmanagement/costmanagement-metrics-rhel9-operator 1780946239
    fixed: vendor fix RHSA-2026:27998
  • Red Hat Discovery 2 discovery/discovery-ui-rhel9 1782166952, discovery/discovery-server-rhel9 1782159791
    fixed: vendor fix RHSA-2026:29197
show 13 more
  • Red Hat Enterprise Linux AppStream (v. 8) glibc-utils 2.28-251.el8_10.37, compat-libpthread-nonshared 2.28-251.el8_10.37
    fixed: vendor fix RHSA-2026:20587
  • Red Hat Enterprise Linux AppStream (v. 9) glibc-utils 2.34-270.el9_8, glibc-locale-source 2.34-270.el9_8
    fixed: vendor fix RHSA-2026:20597
  • Red Hat Enterprise Linux AppStream (v. 10) glibc-utils 2.39-124.el10_2, glibc-locale-source 2.39-124.el10_2
    fixed: vendor fix RHSA-2026:20594
  • Red Hat Enterprise Linux BaseOS (v. 8) nscd 2.28-251.el8_10.37, glibc 2.28-251.el8_10.37, libnsl 2.28-251.el8_10.37, nss_db 2.28-251.el8_10.37, glibc-common 2.28-251.el8_10.37, glibc-gconv-extra 2.28-251.el8_10.37, +3 more
    fixed: vendor fix RHSA-2026:20587
  • Red Hat Enterprise Linux BaseOS (v. 9) nscd 2.34-270.el9_8, glibc 2.34-270.el9_8, libnsl 2.34-270.el9_8, glibc-common 2.34-270.el9_8, glibc-gconv-extra 2.34-270.el9_8, glibc-all-langpacks 2.34-270.el9_8, +1 more
    fixed: vendor fix RHSA-2026:20597
  • Red Hat Enterprise Linux BaseOS (v. 10) glibc 2.39-124.el10_2, libnsl 2.39-124.el10_2, glibc-common 2.39-124.el10_2, glibc-gconv-extra 2.39-124.el10_2, glibc-all-langpacks 2.39-124.el10_2, glibc-minimal-langpack 2.39-124.el10_2
    fixed: vendor fix RHSA-2026:20594
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) nss_db 2.34-270.el9_8, nss_hesiod 2.34-270.el9_8, glibc-benchtests 2.34-270.el9_8
    fixed: vendor fix RHSA-2026:20597
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) nss_db 2.39-124.el10_2, nss_hesiod 2.39-124.el10_2, glibc-benchtests 2.39-124.el10_2
    fixed: vendor fix RHSA-2026:20594
  • Red Hat Enterprise Linux CRB (v. 8) nss_hesiod 2.28-251.el8_10.37, glibc-benchtests 2.28-251.el8_10.37
    fixed: vendor fix RHSA-2026:20587
  • Red Hat Hardened Images glibc 2.42-12.hum1, glibc32 2.42-12.hum1, glibc-utils 2.42-12.hum1, glibc-common 2.42-12.hum1, glibc-benchtests 2.42-12.hum1, glibc-gconv-extra 2.42-12.hum1, +5 more
    fixed: vendor fix RHSA-2026:12740
  • Red Hat Insights proxy 1.5 insights-proxy/insights-proxy-container-rhel9 1780420428
    fixed: vendor fix RHSA-2026:22634
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1781525684, rhui5/rhua-rhel9 1781525739, rhui5/haproxy-rhel9 1781525671, rhui5/rhua-tp-rhel9 1787241260, rhui5/installer-rhel9 1781525693, rhui5/installer-tp-rhel9 1787135742, +1 more
    fixed: vendor fix RHSA-2026:58981
  • Red Hat Cost Management 4 costmanagement/costmanagement-metrics-operator-bundle 1780989656 Red Hat Hardened Images libnsl 2.42-12.hum1, nss_db 2.42-12.hum1, nss_hesiod 2.42-12.hum1, compat-libpthread-nonshared 2.42-12.hum1 Red Hat Update Infrastructure 5 rhui5/cds-tp-rhel9 1787241206, rhui5/cds-kubernetes-rhel9 1781525677
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • sourceware.org https://sourceware.org/bugzilla/show_bug.cgi?id=33980 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • The GNU C Library glibc
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.