VulnerabilityPublished 18 Oct 2026

CVE-2026-98813: Linux kernel · bpf: Hold map BTF for the memory allocator destructor record

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in b506f5699e145196ee29d76cf1ca1cbb2202c055 : patch Linux kernel soon.

Data as of 26 Oct 2026, 09:44 UTC

Severity

High

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

Patch: Available – fixed in b506f5699e145196ee29d76cf1ca1cbb2202c055, ab39974240a0cff765f3bb9cce81d8001ffdb144, 6.19 +1

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 b506f5699e145196ee29d76cf1ca1cbb2202c055, ab39974240a0cff765f3bb9cce81d8001ffdb144, 6.19 or 6.13.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=6.12.112 <6.13 >=6.18.55 <6.19	Fixed in b506f5699e145196ee29d76cf1ca1cbb2202c055 ab39974240a0cff765f3bb9cce81d8001ffdb144 6.19 6.13
LinuxLinux	Affected =7.0	Fixed in–

AI-suggested

A fix is available and has been applied in Linux kernel versions 6.13 and 6.19 and later. Users should upgrade to these or later kernel versions to remediate this issue. No additional mitigation actions are indicated by the vendor advisory.

Description

CVE-2026-98813 is a use-after-free vulnerability in the Linux kernel's BPF subsystem related to handling map BTF references in the memory allocator destructor record. The flaw occurs when a map's BTF reference is released prematurely while deferred work still accesses it, leading to a kernel slab-use-after-free error. This issue affects certain Linux kernel versions prior to 6.13 and 6.19, as well as version 7.0. The vulnerability has been fixed by ensuring the map BTF reference is held until the duplicated record is fully freed during deferred destruction.

Impact

The vulnerability can cause a kernel use-after-free error, potentially leading to kernel crashes or instability when freeing BPF maps with deferred destruction. This impacts system reliability and could be leveraged to cause denial of service. There is no indication of known exploitation in the wild or direct privilege escalation from the provided data.

Summary

This vulnerability involves the Linux kernel's BPF memory allocator destructor record handling. The function bpf_ma_set_dtor() duplicates the map's record, which contains references to the map's BTF (BPF Type Format). The problem arises because the duplicated record holds pointers into the map's BTF, which can be freed prematurely when the map is freed, while deferred RCU callbacks still use the duplicated record. This leads to a use-after-free condition detected by Kernel Address Sanitizer (KASAN) during workqueue processing. The fix retains a reference to the map's BTF in the destructor context until the duplicated record is fully freed, preventing the BTF from being freed too early.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:44 UTC

Technical details

References

Community reviews

Related threats