In the Linux kernel, the following vulnerability has been resolved:
ip6_tunnel: clear skb2->cb[] in ip4ip6_err()
Oskar Kjos reported the following problem.
ip4ip6_err() calls icmp_send() on a cloned skb whose cb[] was written
by the IPv6 receive path as struct inet6_skb_parm. icmp_send() passes
IPCB(skb2) to __ip_options_echo(), which interprets that cb[] region
as struct inet_skb_parm (IPv4). The layouts differ: inet6_skb_parm.nhoff
at offset 14 overlaps inet_skb_parm.opt.rr, producing a non-zero rr
value. __ip_options_echo() then reads optlen from attacker-controlled
packet data at sptr[rr+1] and copies that many bytes into dopt->__data,
a fixed 40-byte stack buffer (IP_OPTIONS_DATA_FIXED_SIZE).
To fix this we clear skb2->cb[], as suggested by Oskar Kjos.
Also add minimal IPv4 header validation (version == 4, ihl >= 5).
References
Configurations
Configuration 1 (hide)
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History
04 May 2026, 18:26
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | CWE-787 | |
| First Time |
Linux
Linux linux Kernel |
|
| References | () https://git.kernel.org/stable/c/1063515ce15ff31065c4e7f8265f4c2fd3c54876 - Patch | |
| References | () https://git.kernel.org/stable/c/2cc6e3b0fe0f0242d1f530a93a4924f48ab85ba5 - Patch | |
| References | () https://git.kernel.org/stable/c/2edfa31769a4add828a7e604b21cb82aaaa05925 - Patch | |
| References | () https://git.kernel.org/stable/c/4a622658f384b03560834cbe8ffcfe69a278f7c8 - Patch | |
| References | () https://git.kernel.org/stable/c/590f622669b97eaf7b57a1de7b0a6e68c5d8b2c3 - Patch | |
| References | () https://git.kernel.org/stable/c/a0c4ce9900a108eaf55d0f3b399cb55999647d39 - Patch | |
| References | () https://git.kernel.org/stable/c/d6621f60192fe10c047a4487be42a6f4c150707f - Patch | |
| References | () https://git.kernel.org/stable/c/ea9f65b27c8404e164848ebff1443310fd187629 - Patch | |
| CPE | cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* |
03 May 2026, 07:16
| Type | Values Removed | Values Added |
|---|---|---|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 9.8 |
01 May 2026, 15:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-01 15:16
Updated : 2026-05-04 18:26
NVD link : CVE-2026-43037
Mitre link : CVE-2026-43037
CVE.ORG link : CVE-2026-43037
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-787
Out-of-bounds Write