bpf: Don't resurrect a scalar id dropped by collect_linked_regs()
check_cond_jmp_op() copies the compared registers into
env->{false,true}_reg{1,2} before collect_linked_regs() runs and copies
those snapshots back into both branch states afterwards.
collect_linked_regs() records at most LINKED_REGS_MAX members of a
linked registers group in the jump history and calls clear_scalar_id()
for every member that does not fit. The compared register is not exempt
from that.
As a consequence, sync_linked_regs() might adjust ranges for more
registers than bpf_bt_sync_linked_regs() can propagate precision to.
Collect the linked registers before the snapshots are taken instead.
This might lead to some unnecessary clear_scalar_id's, but from
previous testing situations with many linked registers are
extremely rare.
Metrics
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Solution
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Workaround
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Fri, 25 Sep 2026 16:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-665 |
Fri, 25 Sep 2026 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: bpf: Don't resurrect a scalar id dropped by collect_linked_regs() check_cond_jmp_op() copies the compared registers into env->{false,true}_reg{1,2} before collect_linked_regs() runs and copies those snapshots back into both branch states afterwards. collect_linked_regs() records at most LINKED_REGS_MAX members of a linked registers group in the jump history and calls clear_scalar_id() for every member that does not fit. The compared register is not exempt from that. As a consequence, sync_linked_regs() might adjust ranges for more registers than bpf_bt_sync_linked_regs() can propagate precision to. Collect the linked registers before the snapshots are taken instead. This might lead to some unnecessary clear_scalar_id's, but from previous testing situations with many linked registers are extremely rare. | |
| Title | bpf: Don't resurrect a scalar id dropped by collect_linked_regs() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-25T10:23:54.242Z
Reserved: 2026-09-25T10:19:56.071Z
Link: CVE-2026-98042
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-25T11:17:32.987
Modified: 2026-09-25T11:17:32.987
Link: CVE-2026-98042
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-09-25T16:00:18Z