[CVE-2026-74360][MODERATE 7.0] bpf: Reject exclusive maps for bpf_map_elem iterators [ Upstream

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-74360
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: bpf: Reject exclusive maps for bpf_map_elem iterators [ Upstream
Commit: 5cf2c85b1231218a3e3e9f188afb4fe2e17903d5
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5cf2c85b1231218a3e3e9f188afb4fe2e17903d5
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74360
Analysis date: Sat, 15 Aug 2026 19:03:30 -0400
ActionableScore: 6
ActionableScore lower bound: 5
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
A bpf_map_elem iterator could bypass exclusive BPF map compatibility checks and expose protected map values as writable data, allowing a local actor with BPF iterator capability and map access to read or modify state intended only for the matching trusted BPF program.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-74360 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74360

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: MODERATE 7.0
Manual review required: YES

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

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-74360	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H';CWE-284;CWE-862;CWE-863;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L';BEST CVSS score: '7.8';DESCR 'A bpf_map_elem iterator could be attached to an exclusive BPF map without going through the normal program compatibility check that enforces the map binding to a single trusted program hash. Because the iterator exposes map values as writable buffers, a local actor with BPF iterator capability and access to the map fd could read or modify data that was intended to be reachable only from the matching trusted BPF program. For the CVSS the PR:L is used because triggering requires local BPF control plane access or an equivalent delegated capability, but not necessarily full administrator control in practical deployments. The issue is not network reachable and is triggered through local BPF syscalls and iterator attachment. Impact is primarily an access control bypass with confidentiality and integrity risk for protected map contents, and availability impact is possible if modified map state disrupts the trusted BPF program behavior.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 7)  SKIP CVE-2026-74360 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: baefdbdf6812e120c9fba9cfb101d3656f478026 YES  NO NO unknown 	MAYBE	BPF SIMPLEFIX HARDWARE  KPANIC INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK KPANIC INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN6 DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=6
ActionableScoreLower=5

## 1. ActionableScore

* Conservative score: 5
* Paranoid score: 6
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Triggered signals:

* Security-boundary bypass with practical sensitive-object access: +2
  Exclusive BPF maps are intended to be reachable only from the single matching trusted program hash. The iterator attach path bypassed that compatibility check.

* Practical exploit chain demonstrated or strongly implied: +1
  The commit directly states that bpf_map_elem iterator binds the target map at attach time and never reaches check_map_prog_compatibility().

* Confidentiality impact plausible: +1
  The iterator can expose protected exclusive map values that were intended to be reachable only by the matching program.

* Integrity impact plausible: +1
  The iterator exposes the map value as writable buffer, so protected map contents may be modified outside the intended trusted-program boundary.

* Availability impact possible: +1
  Corrupting protected BPF map state may disrupt the trusted BPF program behavior, though this is secondary and workload-dependent.

Negative or limiting signals:

* Requires privileged BPF capability in typical deployments: -1 conservative
  In many hardened products unprivileged BPF is disabled and attaching iterators generally requires CAP_BPF, CAP_SYS_ADMIN, or equivalent privilege. I use -1 rather than -2 because the bug bypasses a meaningful BPF security boundary rather than being only a full-root self-DoS.

* Rare or specialized feature exposure: -1 conservative
  Exclusive maps and signed BPF loader workflows are not universal default paths.

Not triggered:

* No generic memory corruption signal.
  The patch shows an authorization and binding check bypass, not UAF, OOB write, double free, type confusion, or arbitrary write into kernel memory.

* No remote/network-triggerable signal.
  The path is local BPF control plane access.

## 3. Reachability analysis

The bug is reachable by a local actor who can attach a bpf_map_elem iterator and obtain or use a file descriptor for an exclusive BPF map. In typical production configurations, this is not fully unprivileged because BPF loading and iterator attachment are usually gated by CAP_BPF, CAP_SYS_ADMIN, CAP_NET_ADMIN, root-controlled sysctls, or product policy. However, the attacker does not necessarily need full host-root authority in practical deployments if BPF control is delegated to a service, loader, container root, or reduced-capability account.

Namespaces and containers matter. If a container or service has delegated BPF privileges or access to relevant map fds, this becomes more actionable than a normal root-only bug. If BPF is fully restricted to trusted host root and exclusive maps are not used, exposure is much lower.

The path is not network reachable. Exploitation depends on local BPF control plane access and use of exclusive maps.

## 4. Severity interpretation

This behaves more like an actionable Moderate or low-end Important candidate than an ordinary Moderate. The issue is not memory corruption and does not by itself demonstrate arbitrary kernel code execution or classic LPE. The serious part is that it bypasses an intended BPF access-control boundary and exposes protected map values as writable data.

Realistic impact depends heavily on what the exclusive map stores. If it contains trusted policy, enforcement state, security decisions, or data used by signed BPF programs, integrity impact can be significant. If it stores only non-sensitive telemetry, impact may be much lower.

## 5. One-sentence report phrase

A bpf_map_elem iterator could bypass exclusive BPF map compatibility checks and expose protected map values as writable data, allowing a local actor with BPF iterator capability and map access to read or modify state intended only for the matching trusted BPF program.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

This should not be auto-closed because it is a security-boundary bypass in BPF with writable access to protected map contents. Manual review should determine whether affected products enable exclusive maps, signed BPF loader workflows, delegated BPF privileges, or service/container access to relevant map fds.

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

Patch: bpf: Reject exclusive maps for bpf_map_elem iterators [ Upstream
Commit: 5cf2c85b1231218a3e3e9f188afb4fe2e17903d5
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5cf2c85b1231218a3e3e9f188afb4fe2e17903d5

Changed files:
  kernel/bpf/map_iter.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=5cf2c85b1231218a3e3e9f188afb4fe2e17903d5

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

The original Linux kernel CVE announcement for CVE-2026-74360 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74360

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:L/UI:N/S:U/C:L/I:H/A:L
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 7.8

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: 5
  Paranoid ActionableScore: 6

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: MODERATE
KPANIC detected for this report: YES
Published priority for this report (same as in Subject): MODERATE 7.0

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).