CVE Intelligence
Unknown

CVE-2026-80733 — net: remove WARN_ON_ONCE() from sk_mc_loop()

In the Linux kernel, the following vulnerability has been resolved: net: remove WARN_ON_ONCE() from sk_mc_loop() sk_mc_loop() can be called for sockets that are neither AF_INET nor AF_INET6 (e.g. AF_PACKET sockets when sending packets via raw/packet socket over virtual devices such as VRF or ipvlan). In such cases, sk_family is not AF_INET/AF_INET6 and sk_mc_loop() falls through the switch statement and triggers WARN_ON_ONCE(1). Non-INET sockets do not support IP_MULTICAST_LOOP or IPV6_MULTICAST_LOOP options, so loopback should default to true without generating a warning.

Published Sep 3, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.18%
ahead of 7% of scored CVEs · Oct 26, 2026
Affects
Linux
Linux
CVSS base
—
Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and < 97133c4d42654578fab95abe47359ebe784dde18≥ f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and < f625c742b33dc137c209dd13d1c5f12b1c18d71c≥ f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and < ad7fa2f411cb30f63d6725f111be134064cdb718≥ f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and < d2adc4e80b29e58b5162ae09f0f657a215806c8c≥ f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and < ad7dbb1d14b1b4406eca8ef9478e8de312ba0cfe≥ f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and < c8f256dc849205ccb2bd78bd99a3497b972b44e0≥ f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and < 0d75f2c1d0764efa756ad9c1e078d8c09ea8fc1f≥ f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and < b8a39a09ae4eaae04309e1e38ed6a1101d967496
and 7 more version c91f81773cd4bbebfe744e9ab30a7ce093f9b930version c8c30b2b17f2133e953850c547e3902c3a3d80e2version 3fe207e4637a2e792c46a08666aa722f77d7f8f7≥ 3.14.40 and < 3.15≥ 3.18.13 and < 3.19≥ 3.19.6 and < 3.20version 4.0
Vulnerable CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 26, 2026 · 11 reading(s) · max 0.18%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Not enough vector or weakness data: use the affected application’s logs as a starting point.
application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Record published
    Oct 15, 2026
  • Affected products added · linux/linux
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Received
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Sep 3, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

8 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-99092 riscv: patch: fix handling of bpf-jit execmem addresses 21h
  • CVE-2026-99093 mm: don't schedule deferred kernel page table freeing while booting 21h
  • CVE-2026-99095 drm/vc4: drain the hangcheck timer and works on V3D unbind 21h
  • CVE-2026-99096 io_uring/register: don't exempt disabled rings from task restrictions 21h
  • CVE-2026-99097 tee: shm: reject zero-sized allocations in tee_dyn_shm_alloc_helper() 21h
  • CVE-2026-99098 dm-integrity: fix buffer overflow in inline mode with large tag size 21h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CVSS score published by NVD, the CNA, CISA or GitHub so far.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-80733 is "net: remove WARN_ON_ONCE() from sk_mc_loop()", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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