Security readout for executives and security teams
Plain-English summary
CVE-2026-43339 is a Linux kernel IPv6 use-after-free bug. A local user with some privileges could potentially crash the system or gain broader control. It is high priority for Linux servers, appliances, and workloads where untrusted users or containers can interact with networking features.
Executive priority
Treat as high priority, especially for shared Linux infrastructure. This is not described as internet-remote or actively exploited, but the possible impact is severe once local access exists. Patch through normal emergency or accelerated kernel update processes based on exposure.
Technical view
The flaw is in the Linux kernel IPv6 addrconf_permanent_addr() path. A warning message could access an IPv6 object after possible deletion. The upstream fix reorders statements and moves the warning outside idev->lock. CVSS 3.1 is 7.8: local, low complexity, low privileges, no user interaction, high CIA impact.
Likely exposure
Exposure is limited to affected Linux kernels with IPv6 code present. The source bundle lists Linux as affected and references stable kernel fixes, but exact distribution package versions are not provided. Systems allowing local shell, container, or low-privileged workload access deserve faster review.
Exploitation context
No active exploitation is stated in the provided sources, and KEV is false. The CVSS vector indicates exploitation requires local access and low privileges, not remote network-only access. Impact could include privilege escalation or denial of service if the use-after-free is practically exploitable.
Researcher notes
The public record describes a resolved kernel bug but does not provide distro package mappings or exploit evidence. The affected-version data in the bundle is commit and version oriented, so validation should rely on vendor advisories plus the listed stable commits.
Mitigation direction
- Apply Linux kernel updates from your OS or appliance vendor when available.
- Prioritize multi-user hosts, container platforms, and systems running untrusted local workloads.
- Review the referenced stable kernel commits for fixed upstream branches.
- If updates are unavailable, check vendor guidance for supported mitigations or workarounds.
Validation and detection
- Inventory Linux kernel versions across servers, containers hosts, appliances, and cloud images.
- Compare installed kernels with vendor advisories and upstream stable fix commits.
- Confirm patched systems booted into the updated kernel, not only installed it.
- Monitor vendor security channels for corrected package version mappings.
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.
CVE-2026-43339 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/eec49a33611f20336b357b3953df44f1a02049e8CVE reference, Linux
- https://git.kernel.org/stable/c/bacc7f31085c9820922f00bc7d79756ffa13123aCVE reference, Linux
- https://git.kernel.org/stable/c/7bfafa1b0cd582983ebec6bb20f0a435528fe567CVE reference, Linux
- https://git.kernel.org/stable/c/7d9f2f4aabd116ca68fbdab5d8fb8dac74c2ea1eCVE reference, Linux
- https://git.kernel.org/stable/c/25357b670afb5b517096da783abaa5cc4bf8359eCVE reference, Linux
- https://git.kernel.org/stable/c/3cd4efb5df72843dfac892d0b3c7a4a8bd926b65CVE reference, Linux
- https://git.kernel.org/stable/c/2d88ed7fa000e19c2dc0fa31b3a849e3f5bca5c1CVE reference, Linux
- https://git.kernel.org/stable/c/fd63f185979b047fb22a0dfc6bd94d0cab6a6a70CVE 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.