Answer in brief
CVE-2026-99275 records a Unknown severity vulnerability in smb: client: reject short SESSION_SETUP responses. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=5478f9ba9a34d660eb3227dcd16314689c51f946 <df63e01933886153e40706483b9635b2456ad91f || >=5478f9ba9a34d660eb3227dcd16314689c51f946 <4d8930afa3446041358a7db33e7b23a0bb9459b5 | df63e01933886153e40706483b9635b2456ad91f, 4d8930afa3446041358a7db33e7b23a0bb9459b5 |
| Linux/Linuxgeneric | 3.6 | Not reported |
Published upstream
Nov 7, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 7, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 7, 2026
In the Linux kernel, the following vulnerability has been resolved: smb: client: reject short SESSION_SETUP responses smb2_check_message() accepts frames shorter than struct smb2_pdu when the SMB2 status is non-zero, before the minimum-PDU check added by b4694f269e66d. A 64-byte STATUS_MORE_PROCESSING_REQUIRED SESSION_SETUP response is therefore accepted even though it cannot contain the SecurityBufferOffset and SecurityBufferLength fields. The parser then reads those fields from stale bytes left in the reused receive buffer by an earlier frame. With a long stale SecurityBufferLength, decode_ntlmssp_challenge() copies up to about 64 KB from beyond the receive object and sends the data back to the server in the NTLMv2 AUTHENTICATE target info. Reject short MPR SESSION_SETUP responses before the short-error path, and validate SecurityBufferOffset + SecurityBufferLength against the received response length before decoding the challenge. The ordering bypass is not new: the short-error early return predates b4694f269e66d, and the unvalidated SecurityBufferLength read predates the 2016 raw NTLMSSP split in 166cea4dc3a4, so all supported stable trees are affected. Reproduced on 6.6.87.2; the path is unchanged on mainline.
Quoted source text, attributed separately from HOL analysis.