Improper Handling of Length Parameter Inconsistency in Net-CIDR-Lite - CVE-2026-40199
Published: July 28, 2026
Vulnerability details
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to application mishandles IPv4 mapped IPv6 addresses, which may allow IP ACL bypass. _pack_ipv6() includes the sentinel byte from _pack_ipv4() when building the packed representation of IPv4 mapped addresses like ::ffff:192.168.1.1. This produces an 18 byte value instead of 17 bytes, misaligning the IPv4 part of the address. The wrong length causes incorrect results in mask operations (bitwise AND truncates to the shorter operand) and in find() / bin_find() which use Perl string comparison (lt/gt). This can cause find() to incorrectly match or miss addresses. A remote attacker can gain unauthorized access to sensitive information on the system.
Affected software
IBM Qradar SIEM
Fedora
Ubuntu
libnet-cidr-lite-perl (Ubuntu package)
perl-Net-CIDR-Lite
How to mitigate CVE-2026-40199
IBM Qradar SIEM - update to 7.5.0 Update Pack 15 IF05
libnet-cidr-lite-perl (Ubuntu package) - addressed in versions 0.21-1ubuntu0.16.04.1~esm1, 0.21-1ubuntu0.18.04.1~esm1, 0.21-2ubuntu0.1+esm1, 0.22-1ubuntu0.1, 0.22-2ubuntu0.24.04.1, 0.22-2ubuntu0.25.10.1, 0.22-2ubuntu0.26.04.1
perl-Net-CIDR-Lite - addressed in versions 0.23-1.el8, 0.23-1.el10_1, 0.23-1.el10_2, 0.23-1.el10_3, 0.23-1.fc42, 0.23-1.fc43, 0.23-1.fc44
External References
Related Security Bulletins
- Improper Handling of Length Parameter Inconsistency in Net::CIDR::Lite
- Multiple vulnerabilities in IBM QRadar SIEM
- Fedora EPEL 10.2 update for perl-Net-CIDR-Lite
- Fedora EPEL 10.1 update for perl-Net-CIDR-Lite
- Fedora EPEL 8 update for perl-Net-CIDR-Lite
- Fedora EPEL 10.3 update for perl-Net-CIDR-Lite
- Fedora 44 update for perl-Net-CIDR-Lite
- Fedora 42 update for perl-Net-CIDR-Lite
- Fedora 43 update for perl-Net-CIDR-Lite
- Ubuntu update for libnet-cidr-lite-perl