Vulnerability in Linux kernel (CVE-2026-98084)
Summary
Vulnerability in Linux kernel (CVE-2026-98084). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
bpf: backtracking shouldn't clear outer frame R1-R5 for callbacks
When processing calls to bpf_loop() verifier marks R1 (and R4) as
precise. R1 tracks loop iterations number and because of the
'callback_depth < R1' mechanics in check_helper_call() must be marked
precise. However, precision propagation for R1 was broken,
when bpf_loop() call was verified on a second iteration.
Consider the following verification trace:
- main: bpf_loop(nr_loops, callback ...)
- callback: BPF_EXIT
- main: bpf_loop(nr_loops, callback ...)
- ...
While the first visit of the call to bpf_loop() propagated R1
precision as expected, the second call to mark_chain_precision() in
the check_helper_call() set R1, but it was immediately reset when
backtrack_insn() processed preceding BPF_EXIT in the loop deleted in
this patch.
Because of that, the second visit of the call to bpf_loop() injected
checkpoint with R1 not marked as precise. Which could trick the
verifier into accepting unsafe programs. See the next patch for an
example of such program.
Commit is structured in a way to minimize conflicts when
'bpf' would be eventually merged with 'bpf-next'.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-98084 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-98084" on the vendor's site.
CVE-2026-98084 (Linux kernel)
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com
- web git.kernel.org