CVE-2026-98420
Microsoft — ksmbd: follow SMB2 session expiration semantics
Microsoft · Not classified by connected sources
EVRS 0 of 100 Informational
Monitor
Rank 2,821 of 2,960 tracked
Why it scores 0
Evidence available: 2 of 8 signalsNo strong exploitation, disclosure, or severity signal is available for this CVE yet.
- CISA KEVDid not apply
- RansomwareNo data
- Vendor exploitationNo data
- EPSSDid not apply
- Microsoft Exploitability IndexNo data
- Pre-patch disclosureNo data
- KEV recencyNo data
- CVSSNo data
The band answers “how soon”, not “how bad”. No data for: Ransomware, Vendor exploitation, Microsoft Exploitability Index, Pre-patch disclosure, KEV recency, CVSS. Why some signals show no data
Fix
No fixed version identified yetAffected versions
Not identified by the connected sources
Remediation
NVD lists one or more references for this CVE that aren't tagged as a patch or vendor advisory. Review them directly to confirm patch availability and applicability before making a remediation decision.
Evidence
Each value with its source| Measure | Value | Source |
|---|---|---|
| CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. | Not publishedNVD and the CVE record were checked and hold no score. | NVD |
| FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. | 0.002 (13.8th pctl) | FIRST EPSS |
| Actively exploitedWhether a source of record has confirmed attacks using it in the wild. | Not confirmed | Patch Tuesday |
| Public exploit moduleA module existing is not the same as active exploitation. | None known | Metasploit |
| EUVD cross-referenceENISA's record: CVSS 0.0, assigned by Linux. | Listed | ENISA EUVD |
Description
NVDIn the Linux kernel, the following vulnerability has been resolved: ksmbd: follow SMB2 session expiration semantics ksmbd_session_register() destroys valid sessions after ten seconds of inactivity whenever a client starts another SessionSetup exchange. This confuses Session.IdleTime with Session.ExpirationTime. Windows can create additional authenticated sessions on an existing connection, so deleting the older session invalidates its tree connects and makes mapped drives fail with STATUS_NETWORK_NAME_DELETED. The session expiration rules require the server to change a valid session to expired only after its credential expiration time passes. A valid or expired session otherwise keeps its connection from being scavenged. Connections that have not negotiated a dialect, have no sessions, or have only InProgress sessions are disconnected after an implementation-specific timeout. Use the Windows-compatible 45 second value and run the expiration check periodically for both TCP and SMB Direct. Keep zero as an infinite credential expiration time, and count each Valid-to-Expired transition. Set expired sessions to InProgress when they reauthenticate. If authentication fails, remove the session from the global and per-connection tables immediately, including SMB3 multichannel connections. Retain protection against abandoned SessionId-zero exchanges by allowing only one InProgress authentication per connection. Additional exchanges fail with STATUS_INSUFFICIENT_RESOURCES, and stale InProgress sessions are reaped after the same 45 second setup timeout. This bounds the original unauthenticated memory-exhaustion path without evicting established sessions.