CVE-2026-89633

Not enough EPSS history yet.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix OOB read/write from unvalidated DataOffset in coalesce_t2() coalesce_t2() computes data pointers directly from server-supplied DataOffset fields with no validation against buffer bounds: data_area_of_tgt = (char *)&pSMBt->hdr.Protocol + get_unaligned_le16(&pSMBt->t2_rsp.DataOffset); data_area_of_src = (char *)&pSMBs->hdr.Protocol + get_unaligned_le16(&pSMBs->t2_rsp.DataOffset); data_area_of_tgt += total_in_tgt; ... memcpy(data_area_of_tgt, data_area_of_src, total_in_src); A small DataOffset can push a pointer below the actual byte area, overwriting header fields; a large one can push it past the buffer end, causing out-of-bounds heap reads (source) or writes (target). The BCC overflow guard does not prevent this: BCC reflects how much data is present, while DataOffset controls where in the buffer it starts. The "validate target area" comment present since the function was first written in 2005 was a placeholder that was never implemented. Add lower- and upper-bound checks for both data pointers before the memcpy, and before any target header fields are modified.

• git.kernel.orghttps://git.kernel.org/stable/c/033bc80019f07d158630df4e69b19a49010f54f1
• git.kernel.orghttps://git.kernel.org/stable/c/6343c1da561962688f203362d80d6a3bfa39fa1b
• git.kernel.orghttps://git.kernel.org/stable/c/672cf86aa6aa0fb4012ce4c3b3498df42ad67a4e

No related CVEs by CWE or product.