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CVE-2026-45841· NVD / CVE Program· CNA Linux

netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 0694618cf3e9b120666e31f5f383a6e466d95a0d, 2195574dc6d9017d32ac346987e12659f931d932, 26900306a5a2c3e4f75c643a064525526bb6e5f3; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1.

Low priority for now. Upgrade to Linux Linux 0694618cf3e9b120666e31f5f383a6e466d95a0d, 2195574dc6d9017d32ac346987e12659f931d932, 26900306a5a2c3e4f75c643a064525526bb6e5f3; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO nf_osf_match_one() computes ctx->window % f->wss.val in the OSF_WSS_MODULO branch with no guard for f->wss.val == 0. A CAP_NET_ADMIN user can add such a fingerprint via nfnetlink; a subsequent matching TCP SYN divides by zero and panics the kernel. Reject the bogus fingerprint in nfnl_osf_add_callback() above the per-option for-loop. f->wss is per-fingerprint, not per-option, so the check must run regardless of f->opt_num (including 0). Also reject wss.wc >= OSF_WSS_MAX; nf_osf_match_one() already treats that as "should not happen". Crash: Oops: divide error: 0000 [#1] SMP KASAN NOPTI RIP: 0010:nf_osf_match_one (net/netfilter/nfnetlink_osf.c:98) Call Trace: <IRQ> nf_osf_match (net/netfilter/nfnetlink_osf.c:220) xt_osf_match_packet (net/netfilter/xt_osf.c:32) ipt_do_table (net/ipv4/netfilter/ip_tables.c:348) nf_hook_slow (net/netfilter/core.c:622) ip_local_deliver (net/ipv4/ip_input.c:265) ip_rcv (include/linux/skbuff.h:1162) __netif_receive_skb_one_core (net/core/dev.c:6181) process_backlog (net/core/dev.c:6642) __napi_poll (net/core/dev.c:7710) net_rx_action (net/core/dev.c:7945) handle_softirqs (kernel/softirq.c:622)

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 27, 2026
Updated
Oct 15, 2026
EPSS
0.1% · 6th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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  • when exploit code appears or is weaponized
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel2.6.31 and later · before 5.10.258
  • linux linux kernel5.11 and later · before 5.15.209
  • linux linux kernel5.16 and later · before 6.1.175
  • linux linux kernel6.2 and later · before 6.6.141
  • linux linux kernel6.7 and later · before 6.12.91
  • linux linux kernel6.13 and later · before 6.18.33
  • linux linux kernel6.19 and later · before 7.0.10

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2.6.31affected
    • 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 and later · before cb833bbc1b3c51e08652d3c86298307c07d3f2dbaffected · git
    • 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 and later · before 26900306a5a2c3e4f75c643a064525526bb6e5f3affected · git
    • 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 and later · before 0694618cf3e9b120666e31f5f383a6e466d95a0daffected · git
    • 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 and later · before 8def8fbd23f40e945febe913d04b731012ce0082affected · git
    • 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 and later · before c55940895245d8ef658ab381248a28755218d625affected · git
    • 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 and later · before fb965b1cfe92b28d28b5ebe3116b81dbef9f2d2faffected · git
    • 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 and later · before 9a05e195618a6d474f2bcd5b6376d0ffc2f00366affected · git
    • 11eeef41d5f63c7d2f7fdfcc733eb7fb137cc384 and later · before 2195574dc6d9017d32ac346987e12659f931d932affected · git
    • before 2.6.31not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.10-17.0.10-1
openSUSE:Tumbleweedkernel-sourcebefore 7.0.11-1.17.0.11-1.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-45839May 27, 2026 · bpf: reject negative CO-RE accessor indices in bpf_core_parse_spec()
    31Monitor
  • ← EarlierCVE-2026-45840May 27, 2026 · openvswitch: cap upcall PID array size and pre-size vport replies
    22Monitor
  • Later →CVE-2026-45842May 27, 2026 · slip: reject VJ receive packets on instances with no rstate array
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0694618cf3e9b120666e31f5f383a6e466d95a0dVendor (CNA)
Linux Linux2195574dc6d9017d32ac346987e12659f931d932Vendor (CNA)
Linux Linux26900306a5a2c3e4f75c643a064525526bb6e5f3Vendor (CNA)
Linux Linux8def8fbd23f40e945febe913d04b731012ce0082Vendor (CNA)
Linux Linux9a05e195618a6d474f2bcd5b6376d0ffc2f00366Vendor (CNA)
Linux Linuxc55940895245d8ef658ab381248a28755218d625Vendor (CNA)
Linux Linuxcb833bbc1b3c51e08652d3c86298307c07d3f2dbVendor (CNA)
Linux Linuxfb965b1cfe92b28d28b5ebe3116b81dbef9f2d2fVendor (CNA)
azl3 kernel 6.6.139.1-1 on Azure Linux 3.06.6.141.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)
opensuse:kernel-source7.0.11-1.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-458890 days apartmptcp: do not account for OoO in mptcp_rcvbuf_grow()
    22Monitor
  • CVE-2026-461611 days apartmd/raid10: fix divide-by-zero in setup_geo() with zero far_copies
    22Monitor
  • CVE-2026-461841 days apartsound: ua101: fix division by zero at probe
    22Monitor
  • CVE-2026-4335419 days apartiio: proximity: hx9023s: Protect against division by zero in set_samp_freq
    22Monitor
  • CVE-2026-4341119 days aparttipc: fix divide-by-zero in tipc_sk_filter_connect()
    22Monitor
  • CVE-2026-4323821 days apartnet/sched: act_skbedit: fix divide-by-zero in tcf_skbedit_hash()
    22Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-369 · Divide By Zero

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (10 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records