CVE-2026-71401
Description
A flaw was found in wicked, specifically in its DHCPv4 packet capture code. An integer underflow vulnerability exists where the ni_capture_inspect_udp_header() function fails to validate the IP total length field against the IP header length before performing a subtraction. This oversight allows an unauthenticated attacker on the same network to trigger an out-of-bounds read in the wicked DHCPv4 client (wickedd-dhcp4), potentially leading to a daemon crash and a Denial of Service. No information disclosure has been demonstrated as a result of this issue.
Statement
Red Hat Product Security has determined that this vulnerability does not affect any currently supported Red Hat product. This assessment may evolve based on further analysis and discovery. For more information about this vulnerability and the products it affects, please see the linked references.
Mitigation
To mitigate this issue, if the `wicked` DHCPv4 client is not actively used on a system, the `wickedd-dhcp4` service can be disabled. This prevents the vulnerable component from processing DHCPv4 packets.
To disable the service:
bashDisabling this service will prevent the system from obtaining an IPv4 address via DHCP. A system restart or network service reload may be required for changes to take full effect.
# systemctl stop wickedd-dhcp4
# systemctl disable wickedd-dhcp4
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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