Ubuntu USN · USN-8611-1

GNU C Library vulnerabilities

Published: Mon, 27 Jul 2026 12:24

CVE-2026-5450CVE-2026-4438CVE-2026-5928CVE-2026-6238CVE-2026-4437CVE-2026-4046CVE-2026-5435

Summary

Several security issues were fixed in GNU C Library.

Details

It was discovered that the GNU C Library iconv function incorrectly handled certain IBM character sets. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-4046) It was discovered that the GNU C Library DNS functions incorrectly handled certain DNS server responses when using gethostbyaddr or gethostbyaddr_r. An attacker in a privileged network position could possibly use this issue to cause an application to violate DNS specification or obtain incorrect hostname information. This issue only affected Ubuntu 24.04 LTS. (CVE-2026-4437, CVE-2026-4438) It was discovered that the GNU C Library deprecated debugging functions incorrectly enforced caller-supplied buffer lengths. An attacker could possibly use this issue to cause a denial of service or execute arbitrary code. (CVE-2026-5435) It was discovered that the GNU C Library scanf family of functions contained a heap buffer overflow when processing certain format specifiers. An attacker could possibly use this issue to cause a denial of service or execute arbitrary code. (CVE-2026-5450) It was discovered that the GNU C Library ungetwc function incorrectly handled certain character encodings. An attacker could possibly use this issue to obtain sensitive information or cause a denial of service. (CVE-2026-5928) It was discovered that the GNU C Library deprecated debugging functions incorrectly validated DNS response record data. An attacker could possibly use this issue to cause a denial of service or obtain sensitive information. (CVE-2026-6238)

Recommended actions per Ubuntu release

StackPatch playbook auto-generated per release codename and per affected package.

Ubuntu jammy

glibc→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y glibc
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
glibc-doc→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y glibc-doc
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
glibc-source→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y glibc-source
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc-bin→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc-bin
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc-dev-bin→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc-dev-bin
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc-devtools→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc-devtools
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-amd64→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-amd64
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-amd64→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-amd64
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-i386→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-i386
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-s390→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-s390
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-x32→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-x32
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-i386→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-i386
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-prof→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-prof
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-s390→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-s390
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-x32→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-x32
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
locales→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y locales
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
locales-all→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y locales-all
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
nscd→2.35-0ubuntu3.14apt_upgrade
Standard apt upgrade. Install 2.35-0ubuntu3.14 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y nscd
```
Most apt upgrades restart their service automatically. needrestart lists anything else.

Ubuntu noble

glibc→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y glibc
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
glibc-doc→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y glibc-doc
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
glibc-source→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y glibc-source
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc-bin→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc-bin
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc-dev-bin→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc-dev-bin
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc-devtools→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc-devtools
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-amd64→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-amd64
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-amd64→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-amd64
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-i386→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-i386
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-s390→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-s390
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-x32→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-x32
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-i386→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-i386
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-s390→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-s390
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-x32→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-x32
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
locales→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y locales
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
locales-all→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y locales-all
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
nscd→2.39-0ubuntu8.8apt_upgrade
Standard apt upgrade. Install 2.39-0ubuntu8.8 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y nscd
```
Most apt upgrades restart their service automatically. needrestart lists anything else.

Ubuntu resolute

glibc→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y glibc
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
glibc-doc→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y glibc-doc
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
glibc-source→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y glibc-source
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc-bin→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc-bin
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc-dev-bin→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc-dev-bin
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc-devtools→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc-devtools
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc-gconv-modules-extra→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc-gconv-modules-extra
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-amd64→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-amd64
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-amd64→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-amd64
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-i386→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-i386
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-dev-x32→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-dev-x32
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-i386→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-i386
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
libc6-x32→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y libc6-x32
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
locales→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y locales
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
locales-all→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y locales-all
```
Most apt upgrades restart their service automatically. needrestart lists anything else.
nscd→2.43-2ubuntu2.3apt_upgrade
Standard apt upgrade. Install 2.43-2ubuntu2.3 from the apt repo.
```
sudo apt-get update
sudo apt-get install --only-upgrade -y nscd
```
Most apt upgrades restart their service automatically. needrestart lists anything else.

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