VulnerabilityPublished 18 Oct 2026

CVE-2026-98787: Linux kernel · bpf: Fix missing migration protection in __rhtab_map_lookup_and_delete_batch()

Affects Linux kernelSource CVE Database V5

Not known to be exploited : upgrade to de020dc8049bfb2b22e3b6d99c031feb2e22d112 or 94f41ec5fa578765b74ad5736c2f029e7aabc46d when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in de020dc8049bfb2b22e3b6d99c031feb2e22d112, 94f41ec5fa578765b74ad5736c2f029e7aabc46d

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to de020dc8049bfb2b22e3b6d99c031feb2e22d112 or 94f41ec5fa578765b74ad5736c2f029e7aabc46d.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 818e0084822742fc00eacbf5df3476a5e72c7d0e, < de020dc8049bfb2b22e3b6d99c031feb2e22d112	Fixed in de020dc8049bfb2b22e3b6d99c031feb2e22d112
LinuxLinux	Affected ≥ 818e0084822742fc00eacbf5df3476a5e72c7d0e, < 94f41ec5fa578765b74ad5736c2f029e7aabc46d	Fixed in 94f41ec5fa578765b74ad5736c2f029e7aabc46d
LinuxLinux	Affected =7.2	Fixed in–
Red Hatredhat/kernel`pkg:rpm/redhat/kernel`Other threats	Affected =7.2	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available and has been applied in the Linux kernel commits de020dc8049bfb2b22e3b6d99c031feb2e22d112 and 94f41ec5fa578765b74ad5736c2f029e7aabc46d. Users should update to a kernel version containing these patches to resolve the issue.

Description

A vulnerability in the Linux kernel's BPF subsystem was fixed to address missing migration protection in the function __rhtab_map_lookup_and_delete_batch(). The issue involved improper handling of CPU migration during a delete loop, which could cause a kernel bug due to use of smp_processor_id() in preemptible code. The fix adds migrate_disable()/migrate_enable() calls to prevent task migration during this operation.

Impact

This vulnerability could cause kernel crashes (BUG) due to improper CPU migration handling during batch deletion in the BPF map. It affects system stability but does not indicate direct privilege escalation or information disclosure. No known exploits in the wild have been reported.

Summary

The Linux kernel's BPF component had a flaw where __rhtab_map_lookup_and_delete_batch() called rhtab_delete_elem() under rcu_read_lock() without disabling CPU migration. Since rcu_read_lock() on CONFIG_PREEMPT_RCU does not disable migration, tasks could migrate CPUs during the delete loop, causing smp_processor_id() to be used in preemptible code, triggering a kernel BUG. The patch wraps the delete loop with migrate_disable()/migrate_enable() to provide proper migration protection, consistent with other callers of rhtab_delete_elem().

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:57 UTC

Technical details

References

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