SB2026072886 - Ubuntu update for libnet-cidr-lite-perl
Published: July 28, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 vulnerabilities.
1) Improper authorization (CVE-ID: CVE-2021-47154)
CWE-ID: CWE-285 - Improper Authorization
CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to improper input validation when processing extraneous zero characters at the beginning of an IP address string. A remote attacker can bypass access restrictions based on IP addresses.
2) Improper Validation of Syntactic Correctness of Input (CVE-ID: CVE-2026-40198)
CWE-ID: CWE-1286 - Improper Validation of Syntactic Correctness of Input
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to gain access to modify data on the system.
The vulnerability exists due to the application does not validate IPv6 group count, which may allow IP ACL bypass. _pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups. Inputs like "abcd", "1:2:3", or "1:2:3:4:5:6:7" are accepted and produce packed values of wrong length (3, 7, or 15 bytes instead of 17). The packed values are used internally for mask and comparison operations. find() and bin_find() use Perl string comparison (lt/gt) on these values, and comparing strings of different lengths gives wrong results. This can cause find() to incorrectly report an address as inside or outside a range. A remote attacker can gain unauthorized access to sensitive information on the system.
3) Improper Handling of Length Parameter Inconsistency (CVE-ID: CVE-2026-40199)
CWE-ID: CWE-130 - Improper Handling of Length Parameter Inconsistency
CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
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.
Remediation
Install update from vendor's website.