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CVE Record

CVE-2026-31405: media: dvb-net: fix OOB access in ULE extension header tables

In the Linux kernel, the following vulnerability has been resolved: media: dvb-net: fix OOB access in ULE extension header tables The ule_mandatory_ext_handlers[] and ule_optional_ext_handlers[] tables in handle_one_ule_extension() are declared with 255 elements (valid indices 0-254), but the index htype is derived from network-controlled data as (ule_sndu_type & 0x00FF), giving a range of 0-255. When htype equals 255, an out-of-bounds read occurs on the function pointer table, and the OOB value may be called as a function pointer. Add a bounds check on htype against the array size before either table is accessed. Out-of-range values now cause the SNDU to be discarded.

CriticalCVSS 9.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

A malformed DVB ULE network packet can make an affected Linux kernel read beyond a function-pointer table and potentially call an unintended address. Successful exploitation could compromise confidentiality, integrity, and availability. Practical exposure depends on whether the system uses the vulnerable DVB networking and ULE processing path.

Executive priority

Treat as urgent for systems using DVB ULE with untrusted input because the vulnerable code may call an out-of-bounds function pointer. Rapidly identify those systems and patch them. Do not assume fleet-wide exposure solely from the critical score; confirm whether the affected media networking path is actually used.

Technical view

In handle_one_ule_extension(), an attacker-controlled eight-bit htype can equal 255, while both extension-handler arrays accept only indices 0–254. The resulting out-of-bounds function-pointer read may be invoked. The kernel fix checks htype against the table size and discards invalid SNDUs.

Likely exposure

Potentially exposed systems run an affected Linux kernel and process attacker-controlled DVB ULE traffic through dvb-net. Ordinary Linux systems not using this path may have substantially lower practical exposure. The supplied version data is broad and ambiguous, so confirm status using distribution builds and the listed stable commits.

Exploitation context

The CVSS 3.1 score is 9.8, describing network-reachable, low-complexity exploitation without privileges or user interaction and with potentially complete impact. However, the bundle marks this CVE as absent from KEV and provides no evidence of exploitation in the wild or a public proof of concept.

Researcher notes

The root cause is an off-by-one bounds mismatch: network-derived htype spans 0–255, but the handler tables contain 255 entries. The source establishes possible indirect calling of the out-of-bounds value, but does not demonstrate reliable code execution. Stable fixes add explicit bounds validation before either table access.

Mitigation direction

  • Update to a vendor-supported kernel containing the applicable listed stable fix.
  • Ask the Linux distribution vendor to confirm whether the deployed build is vulnerable or backported.
  • Prioritize systems that actively use DVB networking and receive untrusted ULE traffic.
  • Follow vendor guidance for temporary controls if an immediate kernel update is unavailable.

Validation and detection

  • Inventory kernel versions and identify hosts using DVB networking or ULE processing.
  • Compare each kernel build against vendor advisories and the applicable stable fix commit.
  • Verify the updated kernel is installed, booted, and reported by the running system.
  • Confirm invalid ULE extension types are rejected after remediation using safe regression testing.
Prepared
Confidence
medium
Sources
10

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.

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CVE-2026-31405 mapping review

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

1CVSS vectors
3Timeline events
0ADP providers
9Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2026-31405Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2unaffected
LinuxLinux2.6.12, 0, 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.78, 6.18.19, 6.19.9, 7.0affected
Weakness

CWE details

No CWE listed

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