bpf: Fix divide-by-zero in btf_struct_walk()
Summary
| CVE | CVE-2026-98647 |
|---|
| State | PUBLISHED |
|---|
| Assigner | Linux |
|---|
| Source Priority | CVE Program / NVD first with legacy fallback |
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| Published | 2026-10-18 16:17:17 UTC |
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| Updated | 2026-10-19 10:19:29 UTC |
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| Description | In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix divide-by-zero in btf_struct_walk()
When an access goes past the struct and the last member is a flexible
array, btf_struct_walk() folds the offset back into a single element with
(off - moff) % t->size, but never checks that the element type has a size.
BTF takes an empty struct, so this in program BTF
/* event could be empty */
struct event {
#ifdef HAVE_TIMESTAMP
__u64 ts;
#endif
};
struct batch {
int nr;
struct event events[];
};
divides by zero at prog load time. Getting there needs a PTR_TO_BTF_ID that
is not MEM_ALLOC, e.g. a plain read of a local kptr stashed in a map from a
sleepable program.
Oops: divide error: 0000 [#1] SMP KASAN PTI
RIP: 0010:btf_struct_walk+0x53f/0x1570
Call Trace:
<TASK>
btf_struct_access+0x42a/0xcd0
check_ptr_to_btf_access+0x4dc/0x1160
check_mem_access+0x3a45/0x8740
check_load_mem+0x36a/0xd10
do_check_common+0x3ef0/0xb210
bpf_check+0x6d3b/0x8580
bpf_prog_load+0xf7c/0x2720
__sys_bpf+0xa83/0x3690
__x64_sys_bpf+0xc7/0x150
x64_sys_call+0x1f3f/0x27e0
do_syscall_64+0xe5/0x610
entry_SYSCALL_64_after_hwframe+0x76/0x7e
</TASK>
Reject a zero-sized element type. The fixed array path in the same function
already bails out on the same thing:
btf_struct_walk()
...
/* skip empty array */
if (moff == mtrue_end)
continue;
msize /= total_nelems; |
|---|
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|
| CNA |
Linux |
Linux |
affected 9c5f8a1008a121e4c6b24af211034e24b0b63081 1ea3820937f8022e044c41c6e95c84b02741b45f git |
Not specified |
| CNA |
Linux |
Linux |
affected 9c5f8a1008a121e4c6b24af211034e24b0b63081 172756f02663ad45c889c001c1a8cb4082a01a05 git |
Not specified |
| CNA |
Linux |
Linux |
affected 9c5f8a1008a121e4c6b24af211034e24b0b63081 934e9ba9f8d05656a48624710be67ca4dc8482e6 git |
Not specified |
| CNA |
Linux |
Linux |
affected 9c5f8a1008a121e4c6b24af211034e24b0b63081 63af086cb5fa6f72fd924f86bea4c2194da663a2 git |
Not specified |
| CNA |
Linux |
Linux |
affected 9c5f8a1008a121e4c6b24af211034e24b0b63081 8eb4cd72daad3a9ee63d2281bbdd16ce6d9406b1 git |
Not specified |
| CNA |
Linux |
Linux |
affected 9c5f8a1008a121e4c6b24af211034e24b0b63081 b8fa56722e9c43bcd59c51fe4c7edd5f4158a11b git |
Not specified |
| CNA |
Linux |
Linux |
affected 9c5f8a1008a121e4c6b24af211034e24b0b63081 b0b3dc66529676228cb938cbcad66920f735c223 git |
Not specified |
| CNA |
Linux |
Linux |
affected 5.8 |
Not specified |
| CNA |
Linux |
Linux |
unaffected 5.8 semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 5.15.222 5.15.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.1.189 6.1.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.6.158 6.6.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.12.112 6.12.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18.55 6.18.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.2.9 7.2.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.3 * original_commit_for_fix |
Not specified |
References
| Reference | Source | Link | Tags |
|---|
| git.kernel.org/stable/c/b0b3dc66529676228cb938cbcad66920f735c223 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/b8fa56722e9c43bcd59c51fe4c7edd5f4158a11b |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/172756f02663ad45c889c001c1a8cb4082a01a05 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/1ea3820937f8022e044c41c6e95c84b02741b45f |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/63af086cb5fa6f72fd924f86bea4c2194da663a2 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/934e9ba9f8d05656a48624710be67ca4dc8482e6 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/8eb4cd72daad3a9ee63d2281bbdd16ce6d9406b1 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| CVE Program record |
CVE.ORG |
www.cve.org |
canonical |
| NVD vulnerability detail |
NVD |
nvd.nist.gov |
canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.