CVE-2026-45841

Kernel panic via zero OSF window divisor

Published May 27, 2026 · Updated May 27, 2026

Divide-by-zero in the Linux Kernel netfilter OS fingerprint matcher allows local users with CAP_NET_ADMIN to panic the kernel. nf_osf_match_one() applies ctx->window % f->wss.val in the OSF_WSS_MODULO branch without rejecting a zero fingerprint value. A CAP_NET_ADMIN user must first add the fingerprint through nfnetlink; a matching TCP SYN then causes a divide error and system-wide crash.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Divide-by-zero in the Linux Kernel netfilter OS fingerprint matcher allows local users with CAP_NET_ADMIN to panic the kernel. nf_osf_match_one() applies ctx->window % f->wss.val in the OSF_WSS_MODULO branch without rejecting a zero fingerprint value. A CAP_NET_ADMIN user must first add the fingerprint through nfnetlink; a matching TCP SYN then causes a divide error and system-wide crash.

The record

CVE
CVE-2026-45841
Published
May 27, 2026
Updated
May 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-369, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <2195574dc6d9017d32ac346987e12659f931d932
  2. Affected versionversion=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <8def8fbd23f40e945febe913d04b731012ce0082
  3. Affected versionversion=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <9a05e195618a6d474f2bcd5b6376d0ffc2f00366
  4. Affected versionversion=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <c55940895245d8ef658ab381248a28755218d625
  5. Affected versionversion=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <fb965b1cfe92b28d28b5ebe3116b81dbef9f2d2f
  6. Affected versionversion=2.6.31

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <2195574dc6d9017d32ac346987e12659f931d932; version=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <8def8fbd23f40e945febe913d04b731012ce0082; version=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <9a05e195618a6d474f2bcd5b6376d0ffc2f00366; version=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <c55940895245d8ef658ab381248a28755218d625; version=11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 <fb965b1cfe92b28d28b5ebe3116b81dbef9f2d2f; version=2.6.31

Published CVSS scores

5.5NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-369Divide By Zero
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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