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CVE Record

CVE-2026-64046: net: tls: prevent chain-after-chain in plain text SG

In the Linux kernel, the following vulnerability has been resolved: net: tls: prevent chain-after-chain in plain text SG Sashiko points out that if end = 0 (start != 0) the current code will create a chain link to content type right after the wrap link: This would create a chain where the wrap link points directly to another chain link. The scatterlist API sg_next iterator does not recursively resolve consecutive chain links. meaning this is illegal input to crypto. The wrapping link is unnecessary if end = 0. end is the entry after the last one used so end = 0 means there's nothing pushed after the wrap: end start i v v v [ ]...[ ][ d ][ d ][ d ][ d ][rsv for wrap] Skip the wrapping in this case. TLS 1.3 can use the "wrapping slot" for it's chaining if end = 0. This avoids the chain-after-chain. Move the wrap chaining before marking END and chaining off content type, that feels like more logical ordering to me, but should not matter from functional perspective.

CriticalCVSS 9.8Not KEV-listedUpdated
Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

This is a critical Linux kernel networking/TLS flaw. The reported bug can feed malformed scatterlist structure into kernel crypto handling. The source bundle shows upstream stable fixes, but does not show active exploitation, affected distributions, or a named workaround.

Executive priority

Prioritize remediation as urgent because the CVSS is 9.8 and the flaw is in kernel networking/TLS handling. Focus first on critical Linux infrastructure, internet-facing systems, and platforms where delayed kernel patching creates broad operational risk.

Technical view

In net/tls, when end equals 0 and start is nonzero, code can create consecutive scatterlist chain links. The scatterlist iterator does not recursively resolve that shape, making it illegal input to crypto. Fixes skip unnecessary wrapping and adjust chaining order.

Likely exposure

Exposure is likely limited to systems running affected Linux kernel versions where the kernel TLS path is reachable or used. The bundle lists affected Linux kernel ranges, but not distribution package names, appliances, or required runtime configuration.

Exploitation context

The CVSS vector is network, low complexity, unauthenticated, and no user interaction. However, the bundle marks KEV false and provides no proof-of-concept, exploitation report, or operational exploit details. Active exploitation should not be assumed.

Researcher notes

Evidence is mostly from the CVE text and upstream stable commits. The bundle does not provide a crash reproducer, exploitability analysis, impacted distributions, or confirmation of real-world attacks. Validation should focus on affected kernel lineage and patch presence.

Mitigation direction

  • Update affected Linux kernels to vendor or upstream stable releases containing the referenced fixes.
  • Check Linux distribution advisories for backported packages and reboot requirements.
  • Prioritize externally exposed servers and systems using kernel TLS features.
  • If no package is available, follow vendor guidance for temporary risk reduction.

Validation and detection

  • Inventory Linux kernel versions across servers, containers hosts, and appliances.
  • Compare running kernels against vendor advisories and the affected version ranges in the CVE record.
  • Verify installed kernel packages include the relevant stable fix or vendor backport.
  • Confirm systems have rebooted into the fixed kernel after patch installation.
Prepared
Confidence
medium
Sources
10

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

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CVE-2026-64046 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-2026-64046Attack 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.

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux9aaaa56845a06aeabdd597cbe19492dc01f281ec, 9aaaa56845a06aeabdd597cbe19492dc01f281ec, 9aaaa56845a06aeabdd597cbe19492dc01f281ec, 9aaaa56845a06aeabdd597cbe19492dc01f281ec, 9aaaa56845a06aeabdd597cbe19492dc01f281ec, 9aaaa56845a06aeabdd597cbe19492dc01f281ec, 9aaaa56845a06aeabdd597cbe19492dc01f281ec, 9aaaa56845a06aeabdd597cbe19492dc01f281ec, d529d6c9f7e3aaeac13c4948f79799ccb825f29d, 5.4.14unaffected
LinuxLinux5.5, 0, 5.10.258, 5.15.209, 6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11, 7.1affected
Weakness

CWE details

No CWE listed

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