# CVE-2026-99278: ksmbd: limit sessions on each connection

Status: published. Published: 2026-11-07. Updated: 2026-11-07.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ d7fd1f98607f2cd358e583f9548bdf0173090a86; < 94f8462fc9d5332bc54e91605003c17381e9171a (affected, git); ≥ d7fd1f98607f2cd358e583f9548bdf0173090a86; < dc6aa1ba8b7fff8800ad9bf143f17d308e02ec68 (affected, git); c99ea7855124ca1428a1e59c2b4590aaef34eacf (affected, git); ≥ 7.2.8; < 7.3 (affected, semver). Source: CNA: Linux
- Linux / Linux: 7.3 (affected); ≥ 0; < 7.3 (unaffected, semver); ≥ 7.3.2; ≤ 7.3.* (unaffected, semver); ≥ 7.4-rc1; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/94f8462fc9d5332bc54e91605003c17381e9171a (CNA: Linux)

- https://git.kernel.org/stable/c/dc6aa1ba8b7fff8800ad9bf143f17d308e02ec68 (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-99278; retrieved 2026-11-07; source updated 2026-11-07

Revision: a9b38e54b7287ea98063c67a26896d90890d17665bd7a05e35f9ac642b9bcbd0

Canonical: https://y2.dev/cve/CVE-2026-99278

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.