LiveActive security incident?Get immediate response
CVE Record

CVE-2026-31752: bridge: br_nd_send: validate ND option lengths

In the Linux kernel, the following vulnerability has been resolved: bridge: br_nd_send: validate ND option lengths br_nd_send() walks ND options according to option-provided lengths. A malformed option can make the parser advance beyond the computed option span or use a too-short source LLADDR option payload. Validate option lengths against the remaining NS option area before advancing, and only read source LLADDR when the option is large enough for an Ethernet address.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2026-31752 is a Linux kernel bridge flaw in handling IPv6 Neighbor Discovery options. Malformed network option lengths could make kernel parsing go outside the expected option area or read an undersized link-layer address field. Public sources show kernel fixes, but no CVSS score and no known active exploitation signal.

Executive priority

Treat as a normal-priority kernel/network maintenance item unless critical assets use Linux bridging on untrusted networks. Prioritize patch verification for virtualization, container, network appliance, and industrial environments. There is no sourced evidence of active exploitation.

Technical view

The issue is in br_nd_send(), which walks ND options using attacker-controlled option lengths. The fix validates each option length against the remaining Neighbor Solicitation option area and checks source LLADDR size before reading an Ethernet address. The CVE lists Linux kernel versions as affected, with multiple stable kernel commit references.

Likely exposure

Systems using affected Linux kernels with bridge networking and IPv6 Neighbor Discovery processing are the relevant exposure. This may include servers, virtualization hosts, containers, appliances, and industrial products using Linux bridging. Exact downstream exposure depends on vendor kernel backports and configuration.

Exploitation context

No source in the bundle reports active exploitation, and CISA KEV status is false. The vulnerability involves malformed ND options, so practical reach is likely tied to network adjacency or paths where such traffic reaches a Linux bridge. Public impact details are limited.

Researcher notes

The public description identifies an ND option parser bounds issue but does not state confidentiality, integrity, or availability impact. The stable commits are the best technical source. Avoid assuming exploitability beyond malformed ND option handling until vendor or kernel maintainers publish more detail.

Mitigation direction

  • Update to a kernel containing the referenced stable fixes or your vendor’s patched kernel.
  • Check Linux distribution and appliance advisories for backported fixes.
  • Review Siemens advisories if using listed Siemens products.
  • Reduce unnecessary bridge exposure to untrusted networks where operationally feasible.
  • Monitor vendor guidance because CVSS and impact details are incomplete.

Validation and detection

  • Inventory Linux systems using bridge networking and IPv6.
  • Compare running kernel builds against vendor advisories and patched stable releases.
  • Confirm whether downstream kernels include the br_nd_send option-length validation fix.
  • Check appliance vendor advisories for affected firmware or embedded Linux versions.
  • Document systems where vendor status remains unknown.
Prepared
Confidence
medium
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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 · low confidence lookup

CVE-2026-31752 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
3Timeline events
1ADP providers
11Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxed842faeb2bd49256f00485402f3113205f91d30, ed842faeb2bd49256f00485402f3113205f91d30, ed842faeb2bd49256f00485402f3113205f91d30, ed842faeb2bd49256f00485402f3113205f91d30, ed842faeb2bd49256f00485402f3113205f91d30, ed842faeb2bd49256f00485402f3113205f91d30, ed842faeb2bd49256f00485402f3113205f91d30, ed842faeb2bd49256f00485402f3113205f91d30unaffected
LinuxLinux4.15, 0, 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12, 7.0affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.