GHSA-J6WX-7C3W-595C
Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-13 09:32In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr()
reparse_buf_ptr() reads buf->ReparseDataLength before checking that count covers the full fixed header:
buf = (struct reparse_data_buffer *)((u8 *)io + off);
len = sizeof(*buf); /* 8 bytes */
rdlen = le16_to_cpu(buf->ReparseDataLength); /* offset 4, 2 bytes */
if (count < len || count < rdlen + len) /* check comes after */
struct reparse_data_buffer has ReparseDataLength at offset 4. If a server returns OutputCount < 6, the read at offset 4-5 reaches past the end of the received data. The off+count bounds against iov_len were already validated, but that does not protect against count being smaller than sizeof(*buf).
Split the check: verify count >= sizeof(*buf) before reading ReparseDataLength, then verify count covers the data region.
{
"affected": [],
"aliases": [
"CVE-2026-89632"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-11T20:19:48Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr()\n\nreparse_buf_ptr() reads buf-\u003eReparseDataLength before checking that\ncount covers the full fixed header:\n\n buf = (struct reparse_data_buffer *)((u8 *)io + off);\n len = sizeof(*buf); /* 8 bytes */\n rdlen = le16_to_cpu(buf-\u003eReparseDataLength); /* offset 4, 2 bytes */\n\n if (count \u003c len || count \u003c rdlen + len) /* check comes after */\n\nstruct reparse_data_buffer has ReparseDataLength at offset 4. If a\nserver returns OutputCount \u003c 6, the read at offset 4-5 reaches past\nthe end of the received data. The off+count bounds against iov_len\nwere already validated, but that does not protect against count being\nsmaller than sizeof(*buf).\n\nSplit the check: verify count \u003e= sizeof(*buf) before reading\nReparseDataLength, then verify count covers the data region.",
"id": "GHSA-j6wx-7c3w-595c",
"modified": "2026-09-13T09:32:25Z",
"published": "2026-09-11T21:31:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89632"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/05f78e6cf34ea3a285053bd5999e08e8ac298bd5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/711cf71300d7992f450600df8864917d3538679f"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.