- Exploited
- No known exploitation
- Fix
- Fixed in 7.3
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 7.3.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 20/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The ksmbd SMB server in the Linux kernel did not cap how many authenticated sessions one connection could hold, so a client could repeatedly authenticate and keep an unbounded number of valid sessions open on a single connection. The fix adds a per-connection session limit, defaulting to 64.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: limit sessions on each connection
The pending setup limit only counts InProgress sessions. A client can complete authentication repeatedly and retain an unbounded number of Valid sessions on one connection.
Reserve a connection slot before allocating a session and retain a connection reference while authentication is in progress. The first SMB3 channel takes over that reservation; binding to another connection reserves one slot there. Reauthentication and authentication continuation reuse the existing reservation. Return slots on allocation or insertion failure, channel removal, and final session destruction.
Accept max_sessions_per_connection in reserved startup-request space and default to 64 when older tools leave it zero. Keep the request size and existing field offsets unchanged. Expose the configured limit in procfs. The existing connection limits bound the aggregate number of sessions without a separate global session allocation limit.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure?/25Unknown. No advisory context yet
- Reach20/20Affects Linux kernel (software on nearly every server, desktop or phone)
- Severity?/10Unknown. No CVSS score or vendor rating
- No patch0/5No signal
What would change the score
- Would score about 75 if added to CISA KEV
- Would score about 70 if CISA's SSVC rates exploitation active
- Would score about 42 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 7.3.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- Linux Linux
From 7.2.8 · fixed in 7.3
- Linux Linux
7.3
Evidence 2
- Link
- Link
Corrections
None so far.
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Questions about CVE-2026-99278
Is CVE-2026-99278 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-99278?
Linux: from 7.2.8 before 7.3. Linux: version 7.3.Source: cve.now feed data
How do I fix CVE-2026-99278?
Upgrade to a fixed version: 7.3.Source: cve.now feed data