CVE-2026-43186
Analyzed
Analyzed - Analysis Complete
Heap Buffer Overflow in Linux Kernel IPv6 IOAM
Publication date: 2026-05-06
Last updated on: 2026-05-11
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()
On the receive path, __ioam6_fill_trace_data() uses trace->nodelen
to decide how much data to write for each node. It trusts this field
as-is from the incoming packet, with no consistency check against
trace->type (the 24-bit field that tells which data items are
present). A crafted packet can set nodelen=0 while setting type bits
0-21, causing the function to write ~100 bytes past the allocated
region (into skb_shared_info), which corrupts adjacent heap memory
and leads to a kernel panic.
Add a shared helper ioam6_trace_compute_nodelen() in ioam6.c to
derive the expected nodelen from the type field, and use it:
- in ioam6_iptunnel.c (send path, existing validation) to replace
the open-coded computation;
- in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose
nodelen is inconsistent with the type field, before any data is
written.
Per RFC 9197, bits 12-21 are each short (4-octet) fields, so they
are included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to
0xff1ffc00).
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | From 6.2 (inc) to 6.6.128 (exc) |
| linux | linux_kernel | From 6.7 (inc) to 6.12.75 (exc) |
| linux | linux_kernel | From 6.13 (inc) to 6.18.16 (exc) |
| linux | linux_kernel | From 6.19 (inc) to 6.19.6 (exc) |
| linux | linux_kernel | From 5.16 (inc) to 6.1.165 (exc) |
| linux | linux_kernel | From 5.15 (inc) to 5.15.202 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-787 | The product writes data past the end, or before the beginning, of the intended buffer. |
