bpf: Don't resurrect a scalar id dropped by collect_linked_regs() (CVE-2026-98042) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-98042

bpf: Don't resurrect a scalar id dropped by collect_linked_regs()

Answer in brief

CVE-2026-98042 records a Unknown severity vulnerability in bpf: Don't resurrect a scalar id dropped by collect_linked_regs(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 25, 2026Updated Sep 25, 2026Source checked Sep 25, 2026First seen by HOL Sep 25, 2026Material review Sep 25, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=ec1d77cb0ee98249142dcd0376d76e7a48ba0b31 <e821ff19b8ef08255ff8d8234774ed814637e9bf \|\| >=ec1d77cb0ee98249142dcd0376d76e7a48ba0b31 <73a98f96811e2cb0f4210b1caa8cb322f92f2a2b	e821ff19b8ef08255ff8d8234774ed814637e9bf, 73a98f96811e2cb0f4210b1caa8cb322f92f2a2b
Linux/Linuxgeneric	7.1	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to e821ff19b8ef08255ff8d8234774ed814637e9bf if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 25, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 25, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.