Security readout for executives and security teams
Plain-English summary
A flaw in affected Linux kernels could let a low-privileged local user trigger unsafe access to freed memory while configuring kernel TLS sockets. A successful attack could compromise confidentiality, integrity, and availability. The supplied CVSS score is 7.8 (high), but the sources provide no evidence of active exploitation.
Executive priority
Treat this as a high-priority kernel maintenance issue, especially on shared systems or hosts with untrusted local users. It is less urgent than an unauthenticated remote flaw, and the supplied evidence does not show active exploitation. Use normal expedited change controls and verify the corrected kernel is running.
Technical view
get_netdev_for_sock() may access sk_dst_get(sk)->dev during setsockopt() without the required RCU protection, creating a use-after-free condition. Linux corrected the lifetime handling by using __sk_dst_get() and dst_dev_rcu(). The bonding lower-device callback already operates with RCU.
Likely exposure
Exposure is limited to systems running an affected Linux kernel where a low-privileged local user can reach the relevant kernel TLS socket configuration path. The supplied version data identifies affected releases but contains ambiguous entries, including “0”; confirm applicability through distribution or appliance-vendor advisories and backport records.
Exploitation context
The CVSS vector indicates local access, low complexity, low privileges, and no user interaction. Potential impact spans confidentiality, integrity, and availability. The CVE is not listed as KEV in the supplied bundle, and no supplied source establishes public or active exploitation.
Researcher notes
The key issue is device-pointer lifetime handling outside an RCU read-side section during setsockopt(). The stable commits replace the unsafe access pattern across supported branches. Exact vulnerable boundaries and downstream backports cannot be established confidently from the supplied version list alone; validate against vendor package metadata.
Mitigation direction
- Update to a vendor-supported kernel containing the referenced Linux stable fix.
- Check distribution and appliance advisories for backported fixes and precise affected-version boundaries.
- Restrict untrusted local account access while remediation is pending.
- Review the Siemens advisory if affected Siemens products are deployed.
Validation and detection
- Record the running kernel version and distribution package release on each Linux system.
- Verify the installed package includes the applicable upstream fix or vendor backport.
- Confirm systems rebooted into the remediated kernel after installation.
- Prioritize hosts permitting untrusted or broadly accessible local accounts.
Public sources used
- CVE Program record for CVE-2025-40149
- CVE List V5 record
- Linux stable fix commit 2b1bef126bbb
- Linux stable fix commit e37ca0092dda
- Linux stable fix commit 13159c712563
- Linux stable fix commit f09cd209359a
- Linux stable fix commit feb474ddbf26
- Linux stable fix commit c65f27b9c3be
- Siemens Security Advisory SSA-019113
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-2025-40149 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.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/2b1bef126bbb8d0da51491357559126d567c1deeCVE reference, Linux
- https://git.kernel.org/stable/c/e37ca0092ddace60833790b4ad7a390408fb1be9CVE reference, Linux
- https://git.kernel.org/stable/c/13159c7125636371543a82cb7bbae00ab36730ccCVE reference, Linux
- https://git.kernel.org/stable/c/f09cd209359a23f88d4f3fa3d2379d057027e53cCVE reference, Linux
- https://git.kernel.org/stable/c/feb474ddbf26b51f462ae2e60a12013bdcfc5407CVE reference, Linux
- https://git.kernel.org/stable/c/c65f27b9c3be2269918e1cbad6d8884741f835c5CVE reference, Linux
- https://cert-portal.siemens.com/productcert/html/ssa-019113.htmlCVE reference, siemens-SADP
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.