CVE-2026-98240
net: ip_tunnel: initialize `options_len` before referencing options
Description
In the Linux kernel, the following vulnerability has been resolved: net: ip_tunnel: initialize `options_len` before referencing options The following command triggers a kernel panic: ip link add d0 type dummy; ip link set d0 up ip route add 10.30.0.0/16 \ encap ip id 300 geneve_opts 4660:66:11223344 dev d0 memcpy: detected buffer overflow: 4 byte write of buffer size 0 kernel BUG at lib/string_helpers.c:1044! ... ip_tun_parse_opts.part.0.cold+0x10/0x10 ip_tun_build_state+0x116/0x2a0 On kernels built with GCC 15+ and `CONFIG_FORTIFY_SOURCE`, the fortified `memcpy()` got 0 sized destination with request of 4 bytes length: static int ip_tun_parse_opts_geneve(...) { ... attr = tb[LWTUNNEL_IP_OPT_GENEVE_DATA]; data_len = nla_len(attr); /* == 4 */ struct geneve_opt *opt = ip_tunnel_info_opts(info) + opts_len; memcpy(opt->opt_data, nla_data(attr), data_len); /* ^^^^^^^^^^^^^ 0 since options_len is assigned afterwards */ Fixed by initializing the counter before the options are referenced. Matching what `tunnel_key_opts_set()` already does.
INFO
Published Date :
Oct. 6, 2026, 9:18 a.m.
Last Modified :
Oct. 19, 2026, 10:18 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to include the fix.
- Ensure `options_len` is initialized before use.
- Apply patches that address buffer overflow vulnerabilities.
- Use secure coding practices for memory operations.
References to Advisories, Solutions, and Tools
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CVE-2026-98240.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-98240 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-98240
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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CVE-2026-98240 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-98240 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 19, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/98xxx/CVE-2026-98240.json">CVE-2026-98240</a> -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 06, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: net: ip_tunnel: initialize `options_len` before referencing options The following command triggers a kernel panic: ip link add d0 type dummy; ip link set d0 up ip route add 10.30.0.0/16 \ encap ip id 300 geneve_opts 4660:66:11223344 dev d0 memcpy: detected buffer overflow: 4 byte write of buffer size 0 kernel BUG at lib/string_helpers.c:1044! ... ip_tun_parse_opts.part.0.cold+0x10/0x10 ip_tun_build_state+0x116/0x2a0 On kernels built with GCC 15+ and `CONFIG_FORTIFY_SOURCE`, the fortified `memcpy()` got 0 sized destination with request of 4 bytes length: static int ip_tun_parse_opts_geneve(...) { ... attr = tb[LWTUNNEL_IP_OPT_GENEVE_DATA]; data_len = nla_len(attr); /* == 4 */ struct geneve_opt *opt = ip_tunnel_info_opts(info) + opts_len; memcpy(opt->opt_data, nla_data(attr), data_len); /* ^^^^^^^^^^^^^ 0 since options_len is assigned afterwards */ Fixed by initializing the counter before the options are referenced. Matching what `tunnel_key_opts_set()` already does. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/98xxx/CVE-2026-98240.json">CVE-2026-98240</a> Added Reference https://git.kernel.org/stable/c/0f6a6beb01c068fcd5274eabf22c260039749fea Added Reference https://git.kernel.org/stable/c/455ebeadf714f51e1dbbd6a022c74c9215b1cd76 Added Reference https://git.kernel.org/stable/c/9907325257b4b382f26aafd5d9a8d47915907dd5