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OpenAdvisories
Medium RLSA-2026:19061 2 CVEs

Moderate: glibc security update

Published May 29, 2026 · Updated May 29, 2026

Summary

The glibc packages provide the standard C libraries (libc), POSIX thread libraries (libpthread), standard math libraries (libm), and the name service cache daemon (nscd) used by multiple programs on the system. Without these libraries, the Linux system cannot function correctly.

Security Fix(es):

* glibc: glibc: Incorrect DNS response parsing via crafted DNS server response (CVE-2026-4437)

* glibc: glibc: Invalid DNS hostname returned via gethostbyaddr functions (CVE-2026-4438)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Fixed packages 1

ReleasePackageFixed in
Rocky Linux · 10 glibc 0:2.39-121.el10_2

Vulnerabilities 2

  • High 7.5

    gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response

    Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS…

  • Medium 5.4

    gethostbyaddr and gethostbyaddr_r return invalid DNS hostnames

    Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C library version 2.34 to version 2.43 could result in an invalid DNS hostname being returned to the caller in violation of the DNS sp…

References

  • report
    https://bugzilla.redhat.com/show_bug.cgi?id=2449783
  • report
    https://bugzilla.redhat.com/show_bug.cgi?id=2449777