Security readout for executives and security teams
Plain-English summary
A Linux kernel flaw in CIFS request replay can reuse local variables that were not properly reset. Under the stated conditions, this may let a low-privileged local user compromise confidentiality, integrity, and availability. Systems using affected kernels and CIFS/SMB file shares deserve prompt review.
Executive priority
Treat this as a high-priority kernel maintenance issue, especially for shared Linux systems using CIFS. It is not currently supported as an internet-scale or actively exploited emergency, but the stated potential impact is complete compromise of affected hosts. Require asset identification, vendor-version confirmation, and timely kernel updates.
Technical view
Several CIFS code paths can replay a request after jumping to a replay label. Certain local variables were initialized before, rather than after, that label, allowing stale state during replay. The fix moves required initialization into the replay path. The supplied CVSS 3.1 score is 7.8 with local, low-privilege access and high confidentiality, integrity, and availability impacts.
Likely exposure
Likely exposure is concentrated on hosts running an affected Linux kernel with CIFS functionality in use and request replay occurring. The supplied version data is irregular and includes commit identifiers alongside releases, so administrators should use distribution-specific advisories to determine whether their packaged kernel contains a referenced fix.
Exploitation context
The CVSS vector requires local access and low privileges, with no user interaction. The bundle does not establish whether ordinary CIFS access is sufficient to trigger the flaw. It is not listed as KEV, and the supplied sources provide no evidence of active exploitation or a public exploit.
Researcher notes
No CWE is assigned. Public detail is limited to missing local-variable reinitialization across CIFS replay labels. The bundle does not identify specific variables, trigger conditions, observable failure modes, or demonstrated exploitability. Its flattened affected-version data is ambiguous; branch boundaries and backports should be verified against the CVE record, stable commits, and distribution advisories.
Mitigation direction
- Install a vendor-supported kernel update that incorporates the applicable referenced fix.
- Check distribution security guidance for package-specific affected and fixed versions.
- Prioritize CIFS-enabled systems accessible to untrusted or low-privileged local users.
- If updating is delayed, follow vendor guidance for temporary exposure reduction.
Validation and detection
- Inventory running kernel versions and identify systems using CIFS or SMB mounts.
- Compare each distribution kernel package against its vendor security advisory.
- Confirm the installed kernel includes the applicable referenced stable commit.
- Reboot updated systems and verify the fixed kernel is running.
- Review monitoring data for unexplained CIFS failures, corruption, or kernel instability.
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
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CVE-2026-31693 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
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/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.
CVSS vector scores
1 official scoreWe 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9LinuxVulnerability scoring details
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.
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/c854ab481ece4b3e5f4c2e8b22824f015ff874a5CVE reference, Linux
- https://git.kernel.org/stable/c/1d731e512134495e0ef490ade0e4d91dc0d515ecCVE reference, Linux
- https://git.kernel.org/stable/c/7c9ce68192eef14c777cb6ce17155d2eb2431aeaCVE reference, Linux
- https://git.kernel.org/stable/c/c99e160938b627f6f28edee930e8abc157e84386CVE reference, Linux
- https://git.kernel.org/stable/c/14f66f44646333d2bfd7ece36585874fd72f8286CVE reference, Linux
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.