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Ubuntu 26.04 LTS GNU C Library Critical Denial of Service USN-8611-1

ubuntu
Calendar Grey July 27, 2026
Scroller Ubuntu
Several security issues in GNU C Library for Ubuntu need urgent updates to prevent denial of service attacks.
Ubuntu has addressed multiple vulnerabilities in the GNU C Library affecting versions 22.04, 24.04, and 26.04 LTS, which could lead to denial of service or code execution.

Summary

Several security issues were fixed in GNU C Library.

Software Description:

- glibc: 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 fu...

Read the Full Advisory

Topics%20covered

Topics Covered

security advisory denial of service critical Ubuntu glibc c library

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 26.04 LTS
  libc6                           2.43-2ubuntu2.3

Ubuntu 24.04 LTS
  libc6                           2.39-0ubuntu8.8

Ubuntu 22.04 LTS
  libc6                           2.35-0ubuntu3.14

After a standard system update you need to reboot your computer to make all
the necessary changes.

References

https://ubuntu.com/security/notices/USN-8611-1

CVE-2026-4046, CVE-2026-4437, CVE-2026-4438, CVE-2026-5435,

CVE-2026-5450, CVE-2026-5928, CVE-2026-6238

Severity
critical
Lowest
Low
Medium
High
Critical

Ubuntu Security Notice USN-8611-1

Topics%20covered

Topics Covered

security advisory denial of service critical Ubuntu glibc c library

Package Information

https://launchpad.net/ubuntu/+source/glibc/2.43-2ubuntu2.3
https://launchpad.net/ubuntu/+source/glibc/2.39-0ubuntu8.8
https://launchpad.net/ubuntu/+source/glibc/2.35-0ubuntu3.14

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