Security readout for executives and security teams
Plain-English summary
A flaw in the Linux kernel’s BPF verifier can leave a helper-function pointer unset when a related configuration option is disabled. A local, low-privileged attacker may be able to trigger serious confidentiality, integrity, and availability impacts. The supplied record rates it CVSS 7.8, but provides no evidence of remote reachability or active exploitation.
Executive priority
Prioritize remediation as high for shared Linux hosts, build systems, and platforms running untrusted local workloads. Schedule prompt vendor-supported kernel updates. Internet exposure alone does not establish risk because the stated attack vector is local, but successful exploitation could have severe system-wide consequences.
Technical view
The BPF verifier’s get_helper_proto path could return a NULL helper-function pointer under certain disabled kernel configurations. The fix validates the helper in get_helper_proto and marks the intentionally unused tail_call helper with BPF_PTR_POISON. The CVSS vector indicates local access, low complexity, low privileges, no user interaction, unchanged scope, and high impact across confidentiality, integrity, and availability.
Likely exposure
Exposure is limited to Linux systems running affected kernel builds where the relevant configuration option is disabled and an attacker has local low-privileged access. The bundle lists 5.8, 6.12.50, 6.16.10, and 6.17 as affected, but its version and commit-status data are ambiguous. Confirm applicability through distribution or kernel-vendor guidance.
Exploitation context
The supplied record does not list this CVE in CISA KEV and provides no evidence of exploitation in the wild or a public exploit. The risk model is local privilege-based rather than remote. Treat exploitation status as unconfirmed, while prioritizing systems that permit untrusted local users or workloads.
Researcher notes
The root condition is a potentially NULL BPF helper-function pointer caused by a disabled configuration option. The supplied material does not identify that option, a CWE, crash details, exploit primitives, or confirmed vulnerable distribution packages. The repeated commit and version entries make exact range interpretation uncertain; use the referenced stable commits and vendor advisories for authoritative backport assessment.
Mitigation direction
- Apply a vendor-supported kernel update containing the applicable upstream stable fix.
- Check Linux distribution advisories for corrected package versions and configuration-specific guidance.
- Prioritize multi-user systems and hosts running untrusted local workloads.
- Use vendor guidance for temporary mitigations; none are specified in the supplied sources.
Validation and detection
- Inventory running kernel versions across Linux hosts.
- Check whether deployed kernels contain an applicable referenced stable commit.
- Confirm affected status with each Linux distribution or kernel vendor.
- Verify the updated kernel is running after remediation and reboot.
- Document systems deferred because version applicability remains uncertain.
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
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ATT&CK lookup starting points
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CVE-2025-39990 mapping review
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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/3d429cb1278e995e22995ef117fa96d223a67e93CVE reference, Linux
- https://git.kernel.org/stable/c/6233715b4b714068d6c831d214a4e8792109875aCVE reference, Linux
- https://git.kernel.org/stable/c/e4414b01c1cd9887bbde92f946c1ba94e40d6d64CVE 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.