This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2025:3613 https://access.redhat.com/errata/RHSA-2025:3613

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Extended Update Support

Via RHSA-2025:3614 https://access.redhat.com/errata/RHSA-2025:3614

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7 Extended Lifecycle Support

Via RHSA-2025:3612 https://access.redhat.com/errata/RHSA-2025:3612

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2025:3615 https://access.redhat.com/errata/RHSA-2025:3615

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.2 Advanced Update Support

Via RHSA-2025:3619 https://access.redhat.com/errata/RHSA-2025:3619

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.4 Telecommunications Update Service

Via RHSA-2025:3626 https://access.redhat.com/errata/RHSA-2025:3626

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.6 Telecommunications Update Service

Via RHSA-2025:3625 https://access.redhat.com/errata/RHSA-2025:3625

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Extended Update Support

Via RHSA-2025:3624 https://access.redhat.com/errata/RHSA-2025:3624

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2025:3627 https://access.redhat.com/errata/RHSA-2025:3627

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2025:4025 https://access.redhat.com/errata/RHSA-2025:4025

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7 Extended Lifecycle Support

Via RHSA-2025:4098 https://access.redhat.com/errata/RHSA-2025:4098

Since applying this update on RHEL9 (libxslt-1.1.34-9.el9_5.2.x86_64), libxslt coredumps immediately upon reading an XSL excluding more than 2 namespaces (and issue an error when excluding 2).

To reproduce, run xsltproc command with the following XSL:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
        xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
        xmlns:fo="http://www.w3.org/1999/XSL/Format"
        xmlns:xs="http://www.w3.org/2001/XMLSchema"
        exclude-result-prefixes="xsl fo xs">
</xsl:stylesheet>

Output:
realloc failed !
Segmentation fault (core dumped)

I tried build the 6.14 kernel with libxslt-1.1.34-9.el9_5.2.x86_64 under RHEL 9
Hit realloc failures during build of kernel docs with xml

434570.676644] xsltproc[1425048]: segfault at 0 ip 00007f99c3842f4d sp 00007ffc939cb3b0 error 4 in libxslt.so.1.1.34[ef4d,7f99c383e000+2a000] likely on CPU 0 (core 0, socket 0)
[434570.678118] Code: ba 00 00 00 45 31 ed eb 17 0f 1f 40 00 8b 83 38 01 00 00 49 83 c5 01 44 39 e8 0f 8e 9e 00 00 00 48 8b 83 30 01 00 00 4c 89 e6 <4a> 8b 3c e8 e8 1a c8 ff ff 85 c0 74 d6 48 8b 44 24 08 48 89 ef ff

We are having the same problem as Marc LAUTIER.  We had to roll back to libxslt-1.1.34-9.el9_5.1.x86_64 and it immediately fixed the issue.  We have several exclude-result-prefixes in our code and are getting a Segmentation fault (core dumped).

The rpm libxslt-1.1.34-9.el9_5.3.x86_64 that was made available earlier today fixes the issue for me.

Thanks for the quick fix.