Summary
In the Linux kernel, the following vulnerability has been resolved: net: nfc: nci: Add parameter...
In the Linux kernel, the following vulnerability has been resolved:
net: nfc: nci: Add parameter validation for packet data
Syzbot reported an uninitialized value bug in nci_init_req, which was
introduced by commit 5aca7966d2a7 ("Merge tag
'perf-tools-fixes-for-v6.17-2025-09-16' of
git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools").
This bug arises due to very limited and poor input validation
that was done at nic_valid_size(). This validation only
validates the skb->len (directly reflects size provided at the
userspace interface) with the length provided in the buffer
itself (interpreted as NCI_HEADER). This leads to the processing
of memory content at the address assuming the correct layout
per what opcode requires there. This leads to the accesses to
buffer of skb_buff->data which is not assigned anything yet.
Following the same silent drop of packets of invalid sizes atnic_valid_size(), add validation of the data in the respective
handlers and return error values in case of failure. Release
the skb if error values are returned from handlers innci_nft_packet and effectively do a silent drop
Possible TODO: because we silently drop the packets, the
call to nci_request will be waiting for completion of request
and will face timeouts. These timeouts can get excessively logged
in the dmesg. A proper handling of them may require to exportnci_request_cancel (or propagate error handling from the
nft packets handlers).
Impact
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Frequently Asked Questions
- What is CVE-2025-40043? CVE-2025-40043 is a unknown-severity security vulnerability. No fixed version is listed yet.
- Is there a fix for CVE-2025-40043? No fixed version is listed for CVE-2025-40043 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-40043 exploitable, and should I be worried? Whether CVE-2025-40043 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-40043 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.