[CVE-2026-98274][LOW] net: psp: avoid conflicts with skb->decrypted and sk_validate_xmit_skb() [ Upstream

[CVE-2026-98274][LOW] net: psp: avoid conflicts with skb->decrypted and sk_validate_xmit_skb() [ Upstream

[AL-KERNEL]

CVE: CVE-2026-98274
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: net: psp: avoid conflicts with skb->decrypted and sk_validate_xmit_skb() [ Upstream
Commit: a13cca5ba5375f13cbdab545abfb5e288bef3f78
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a13cca5ba5375f13cbdab545abfb5e288bef3f78
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98274
Analysis date: Sat, 10 Oct 2026 17:08:14 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
No one-sentence report phrase was found.

======================================================================
ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-98274 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98274

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: LOW
Manual review required: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-98274	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98274 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=0 LEGACY=LOW RESULT=DIFF TEMP_DISTANCE_MERGE_SKIP=AEGIS_NO_POSITIVE_SEVERITY_EVIDENCE (independent Legacy and Aegis differ; FINAL: LOW, Aegis: MODERATE_KPANIC)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L';CWE-693;CWE-754;*CWE-20;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.3';DESCR 'PSP and TCP ULP state can coexist on the same socket even though both mechanisms use skb decrypted and sk_validate_xmit_skb with incompatible meanings. This state collision can cause packets to pass through an unexpected validation or encryption path and can at least disrupt the affected connection. A limited confidentiality or integrity impact is plausible if one mechanism treats state produced by the other as proof that security processing has already completed, but no direct memory corruption primitive is established by the available code. For the CVSS the PR:L value in the paranoid score reflects deployments where socket or network configuration is delegated to a container root, service account, or process with restricted capabilities rather than requiring unrestricted host root. The issue is not directly reachable through network traffic alone because creation of the conflicting PSP and TCP ULP state requires local control plane access. Manual review is appropriate because the conflict affects cryptographic state and the exact data path consequences depend on PSP and TLS callback ordering.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2)	MAYBE	REMOTE INIT SIMPLEFIX TEST DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS_AND_CIANNH KPANIC_UNSUPPORTED_REMOVED	-	-	checked

======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=2
ActionableScoreLower=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 2
* Paranoid score: 2
* No floor or cap was applied.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

Conservative signals:

* +1 weak invalid-state or semantic-collision concern. PSP and TCP ULP can coexist even though both assign incompatible meanings to `skb->decrypted` and `sk->sk_validate_xmit_skb()`.
* No negative privilege penalty. The complete privilege boundary for creating both states is not established.

Paranoid additional signal:

* +1 limited availability concern. Conflicting validation or encryption processing can plausibly disrupt the affected connection, but no kernel crash or host-wide DoS is demonstrated.

Important signals not awarded:

* No UAF, OOB access, arbitrary write, refcount error, or other kernel-memory corruption is established.
* Strong semantic reinterpretation was not awarded. The patch does not show attacker-influenced bytes being validated under one representation and later consumed as active control data under another.
* Confidentiality and integrity points were not awarded. Plaintext disclosure, authentication bypass, packet forgery, or modification of a protected resource is not demonstrated.
* Reliable kernel crash was not awarded.
* Remote reachability was not awarded. Traffic alone is not shown to create the conflicting socket state.
* Authorization bypass was not awarded. The new checks enforce feature compatibility rather than restore a mandatory credential, capability, ownership, or LSM decision.
* B5-R does not apply because there is no retry-accumulated heap OOB write.
* B3-PENDING does not apply because no shared-backing write is established.
* B4-PENDING does not apply because there is no demonstrated DENY-to-ALLOW authorization transition.

3. Reachability analysis

The vulnerable state requires PSP association state and a TCP ULP to be installed on the same socket. The patch shows rejection in both relevant setup directions, but it does not establish which actor can complete PSP association setup or which capability namespace governs that operation.

A socket owner may be able to request a TCP ULP in some configurations, while PSP association management may require a separate control-plane actor. The supplied evidence does not establish whether an ordinary user, delegated service, namespace-local administrator, or host administrator can perform the complete sequence. Therefore `HostAdminRequired` and `NamespaceScopedPrivilege` remain `UNKNOWN`.

No prior host setup, namespace-complete trigger, special hardware requirement, or remotely attacker-invocable complete chain is demonstrated. This is not a race.

4. Primitive and severity interpretation

The exact defect is incompatible security-processing state coexisting on one socket. PSP and TLS ULP share `skb->decrypted` and `sk->sk_validate_xmit_skb()` without a compatibility boundary.

This is active socket state, but the supplied data-path context does not show a stale object, lifetime violation, overwrite, disclosure, authorization bypass, or independently useful corruption primitive. It is therefore `CLASS_C`, not Class A or Class B.

The demonstrated consequence is invalid or ambiguous packet-processing state. Connection disruption is technically plausible. Disclosure, packet-authentication bypass, host compromise, and privilege escalation remain speculative and are not scored.

`ImportantCandidate=NO` because no Important-preserving primitive is established. `AutoDowngradeAllowed=YES` because unresolved evidence is limited to the precise operational consequence of the state collision, not a concrete memory-corruption or security-boundary primitive.

5. One-sentence report phrase

PSP and TCP ULP could install incompatible encryption and validation state on the same socket, potentially disrupting packet processing, but the available patch does not establish memory corruption, authorization bypass, information disclosure, or host compromise.

6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Review the PSP and TLS transmit paths to determine whether the shared decrypted flag or callback conflict can bypass encryption or authentication rather than merely break the affected connection.

7. Call-site confidence

Call-site confidence: medium

======================================================================
UPSTREAM PATCH SUMMARY
======================================================================

Patch: net: psp: avoid conflicts with skb->decrypted and sk_validate_xmit_skb() [ Upstream
Commit: a13cca5ba5375f13cbdab545abfb5e288bef3f78
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a13cca5ba5375f13cbdab545abfb5e288bef3f78

Changed files:
  include/net/sock.h
  net/core/sock.c
  net/psp.h
  net/tcp.h
  net/busy_poll.h
  net/phonet/phonet.h
  net/ipv4/tcp_ulp.c
  net/psp/psp_sock.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a13cca5ba5375f13cbdab545abfb5e288bef3f78

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-98274 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98274

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
  The Best / paranoid CVSS score: 5.3

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: 1
  Paranoid ActionableScore: 2

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).