CVE-2026-98487 — net: bridge: mdb: restart port group walk after deletion
In the Linux kernel, the following vulnerability has been resolved: net: bridge: mdb: restart port group walk after deletion br_mdb_flush_pgs() keeps a pointer-to-pointer cursor while walking mp->ports. br_multicast_del_pg() can re-enter the same MDB entry through br_multicast_sg_del_exclude_ports() and unlink other port groups. If the cursor points into one of those groups, the next iteration dereferences a stale cursor and can leave mp->ports pointing at freed memory. A following RTM_GETMDB exposes the dangling pointer: BUG: KASAN: slab-use-after-free in br_mdb_dump Read of size 8 br_mdb_dump rtnl_mdb_dump rtnl_dumpit netlink_dump Reset the cursor to mp->ports after every deletion. The deletion removes at least the selected group, so the restarted walk always makes progress.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+1
- Technical severity (high)+6
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.
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.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux | ≥ a6acb535afb2a3b688a7858f05b61f0433e480d5 and < 46ec55855c972504258c371677ac039ba20e5d12≥ a6acb535afb2a3b688a7858f05b61f0433e480d5 and < ab3c4a4c85f2e1e8d04b5c1770dea8412d21c7fe≥ a6acb535afb2a3b688a7858f05b61f0433e480d5 and < fe2a42789c12eb7c5d3a42191e2cc735a6c35ead≥ a6acb535afb2a3b688a7858f05b61f0433e480d5 and < ab1404ac81154a89fb61ac50ae9a04cd8d4834dcversion 6.8 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | — | — | Linux via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) EPSS over time FIRST
Oct 19, 2026 → Oct 30, 2026 · 12 reading(s) · max 0.20%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Timeline
What happened to this CVE, newest first.
- 2026
- CVSS changed · 7.8
- Source status changed · Published → Received
- Record published
- Affected products added · linux/linux
- Source status changed · → Published
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 18, 2026 – Oct 19, 2026
- 1× Official description updated · Oct 18, 2026 – Oct 18, 2026
References
6 on the record
- git.kernel.org/stable/c/fe2a42789c12eb7c5d3a42191e2cc735a6c35ead
- git.kernel.org/stable/c/ab3c4a4c85f2e1e8d04b5c1770dea8412d21c7fe
- git.kernel.org/stable/c/46ec55855c972504258c371677ac039ba20e5d12
- github.com/advisories/GHSA-vh4c-7r22-fq6w
- git.kernel.org/stable/c/ab1404ac81154a89fb61ac50ae9a04cd8d4834dc
- nvd.nist.gov/vuln/detail/CVE-2026-98487
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-99216 Drivers: hv: Don't reset VMBus connection state on error/exit paths 3d
- Unknown CVE-2026-99215 power: supply: core: prevent unregistering a power supply while a callback runs 3d
- Unknown CVE-2026-99207 scsi: target: Disable interrupts while holding delayed_cmd_lock 3d
- Unknown CVE-2026-99208 drm/xe/oa: Zero OA buffer at allocation 3d
- Unknown CVE-2026-99209 drm/xe: skip eviction of a BO with no resource 3d
- Unknown CVE-2026-99210 accel/rocket: clear rdev on device init failure 3d
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 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-2026-98487 is "net: bridge: mdb: restart port group walk after deletion", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.16% 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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