Security readout for executives and security teams
Plain-English summary
A network client with limited privileges may trigger memory corruption in a Linux SMB file server, potentially affecting confidentiality, integrity, and availability. Exposure requires the kernel ksmbd service and the "streams_xattr" VFS configuration. Systems not using that combination are not indicated as vulnerable by the supplied description.
Executive priority
Treat exposed ksmbd file servers as a high-priority patching item, especially where SMB is reachable across trust boundaries. First establish whether the required "streams_xattr" configuration exists; this sharply narrows exposure. Expedite remediation for matching systems because successful memory corruption could materially disrupt services or compromise protected data.
Technical view
CVE-2024-56626 is a CWE-787 out-of-bounds write in ksmbd_vfs_stream_write. A client-supplied offset can be negative, allowing data to be written outside an allocated buffer when "vfs objects = streams_xattr" is configured. The supplied CVSS 3.1 score is 8.8: network-accessible, low complexity, low privileges, no user interaction, with potentially high confidentiality, integrity, and availability impact.
Likely exposure
Prioritize Linux hosts providing SMB through ksmbd with "streams_xattr" enabled and reachable by untrusted or lower-trust clients. The supplied version data identifies affected Linux kernel lines but is ambiguous about exact ranges; confirm applicability against the running distribution kernel and vendor advisory.
Exploitation context
The supplied CVSS indicates exploitation requires network access and low privileges. No user interaction is required. The source bundle marks this CVE as absent from KEV and provides no evidence of active exploitation or a public exploit. KEV absence does not prove exploitation has never occurred.
Researcher notes
The vulnerable path accepts a client-controlled negative offset that can escape the allocated buffer during stream writes. The exact corruption outcome is not established in the supplied evidence, so code execution should not be assumed. Review the applicable stable-branch patch and downstream backports; distribution kernel versions may not map directly to upstream numbering.
Mitigation direction
- Update to a vendor-supported kernel containing the cited stable fix.
- Check distribution guidance to identify the correct patched package for each kernel line.
- Disable "streams_xattr" where operationally unnecessary until patching is complete.
- Restrict SMB access to trusted networks and authorized clients.
Validation and detection
- Confirm whether ksmbd is enabled and serving SMB connections.
- Review ksmbd.conf for "vfs objects = streams_xattr".
- Record the running kernel and compare it with vendor-fixed package guidance.
- Verify the installed kernel incorporates the applicable cited stable commit.
- Retest SMB service functionality after updating or changing configuration.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-787: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2024-56626 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/1aea5c9470be2c7129704fb1b9562b1e3e0576f8CVE reference, Linux
- https://git.kernel.org/stable/c/8cd7490fc0f268883e86e840cda5311257af69caCVE reference, Linux
- https://git.kernel.org/stable/c/164d3597d26d9acff5d5b8bc3208bdcca942dd6aCVE reference, Linux
- https://git.kernel.org/stable/c/c5797f195c67132d061d29c57a7c6d30530686f0CVE reference, Linux
- https://git.kernel.org/stable/c/313dab082289e460391c82d855430ec8a28ddf81CVE reference, Linux
- https://lists.debian.org/debian-lts-announce/2025/03/msg00001.htmlCVE reference, CVE
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.