Answer in brief
CVE-2026-89630 records a Critical severity (CVSS 9.1) vulnerability in smb: client: restore the data_offset bound in is_valid_oplock_break(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), 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.
CVSS is 9.1. 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), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=83bfbd0bb9025f98fa62b44f93bd67466773d1db <5b16a1967a01ad4496a7206a87c3eb16f1df2b05 || >=83bfbd0bb9025f98fa62b44f93bd67466773d1db <ba22f575de9deeae4ae0859ca4315a7698226237 || 78e718c5aa146063cd70d2cc68297c3ac41f31ee || >=6.18.56 <6.19 | 5b16a1967a01ad4496a7206a87c3eb16f1df2b05, ba22f575de9deeae4ae0859ca4315a7698226237, 6.19 |
| Linux/Linuxgeneric | >=83bfbd0bb9025f98fa62b44f93bd67466773d1db <5b16a1967a01ad4496a7206a87c3eb16f1df2b05 || >=83bfbd0bb9025f98fa62b44f93bd67466773d1db <ba22f575de9deeae4ae0859ca4315a7698226237 | 5b16a1967a01ad4496a7206a87c3eb16f1df2b05, ba22f575de9deeae4ae0859ca4315a7698226237 |
| Linux/Linuxgeneric | 6.19 | Not reported |
Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 11, 2026
In the Linux kernel, the following vulnerability has been resolved: smb: client: restore the data_offset bound in is_valid_oplock_break() Commit 83bfbd0bb902 ("cifs: Remove the RFC1002 header from smb_hdr") changed the quantity this bound is measured against. It used to be srv->total_read minus the 4-byte RFC1002 preamble that total_read then included, so it was the SMB message length. The same commit stopped counting the preamble, and the mechanical substitution to srv->total_read - srv->pdu_size left an expression that is identically zero: standard_receive3() reads MID_HEADER_SIZE() bytes and then exactly pdu_length - MID_HEADER_SIZE() more, adding both to total_read. len is therefore 0, the subtraction below it wraps, and no __u32 DataOffset can exceed the result, so the check from commit 097f5863b1a0 ("cifs: read overflow in is_valid_oplock_break()") no longer rejects anything. Use total_read, which is now the message length on its own.
Quoted source text, attributed separately from HOL analysis.