[CVE-2024-57982][MODERATE 7.0] xfrm: state: fix out-of-bounds read during lookup [ Upstream

[CVE-2024-57982][MODERATE 7.0] xfrm: state: fix out-of-bounds read during lookup [ Upstream

[AL-KERNEL]

CVE: CVE-2024-57982
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: xfrm: state: fix out-of-bounds read during lookup [ Upstream
Commit: a16871c7832ea6435abb6e0b58289ae7dcb7e4fc
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a16871c7832ea6435abb6e0b58289ae7dcb7e4fc
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2024-57982
Analysis date: Mon, 20 Jul 2026 11:00:08 -0400
ActionableScore: 5
ActionableScore lower bound: 2
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
An XFRM state lookup can race with hash table resize and use an hmask that does not match the published hlist array, causing an out-of-bounds read and possible kernel crash, with practical triggering usually requiring local CAP_NET_ADMIN or delegated network namespace control.

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

The original Linux kernel CVE announcement for CVE-2024-57982 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2024-57982

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.

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

CVE-2024-57982	MODERATE	CHECK WITH IMPACT FROM ORIG NN IMPORTANT	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';CWE-125;CWE-362;CWE-667;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.8';DESCR 'XFRM state lookup can race with hash table resize and compute a bucket index using an hmask that does not match the currently published hlist array. This can make the RCU lookup path read beyond the allocated hash table and may lead to invalid hlist traversal or a kernel crash. For the CVSS the PR:L is used for the paranoid score because a reduced capability local actor with CAP_NET_ADMIN in a network namespace may be able to manipulate XFRM state and trigger resize while lookups run in parallel. The issue is not directly network reachable by itself because reliable triggering normally requires local control of XFRM state updates, although network traffic can exercise the lookup side of the race. Impact is at least local denial of service via kernel crash and in the paranoid interpretation may allow limited confidentiality or integrity impact due to out of bounds reads in an RCU protected kernel data structure.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4) 	MAYBE	OOB LINUS SYZBOT  LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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

ActionableScore=5
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

Paranoid scoring used for `ActionableScore=5`:

* Local unprivileged trigger: +1
  In conservative deployments XFRM state manipulation requires CAP_NET_ADMIN, but in namespace-enabled systems a reduced-capability local actor may obtain CAP_NET_ADMIN inside a netns and exercise XFRM state update paths.

* Memory corruption, weak/indirect corruption candidate: +1
  The bug is an out-of-bounds read caused by using an hmask that does not match the currently published hash table pointer. This can make the RCU lookup path interpret memory beyond the hlist array as hash bucket data.

* Memory layout invariant restoration: +1
  The patch restores consistency between interdependent hash-table state: bydst, bysrc, byspi pointers and state_hmask.

* Reliable kernel crash / strong DoS: +1
  The commit explicitly describes an out-of-bounds read during lookup and syzbot reported the issue. Invalid hlist traversal can plausibly crash the kernel.

* Common networking core path or packet-processing path: +1
  XFRM/IPsec state lookup is part of the kernel networking security path and can be exercised by packet processing when XFRM policies/states are configured.

* Availability impact realistic: +1
  The likely practical impact is a host kernel crash or severe fault during lookup. This is system-wide availability impact.

* Hard or unreliable race / special timing required: -1
  Triggering requires lookup and resize to overlap in a narrow concurrency window.

Conservative deductions:

* Requires admin/root/CAP_NET_ADMIN in typical deployments: -2
  In typical host configurations, creating/removing enough XFRM state to force resize is privileged.

## 3. Reachability analysis

Reliable triggering normally requires local ability to manipulate XFRM state tables and cause a concurrent lookup while resize is in progress. On a standard host this generally requires CAP_NET_ADMIN, so the conservative score is low.

Namespaces can change the practical risk. If untrusted users can create network namespaces and obtain CAP_NET_ADMIN inside them, the privilege requirement may drop to a reduced local capability model rather than full host root. Network traffic can exercise the lookup side of the race, but the bug is not directly remote-triggerable by packets alone without local or delegated control over XFRM state changes.

XFRM is not always actively configured, but it is a core kernel networking subsystem and should not be treated as a rare-only path for triage.

Call-site confidence: high. The patch shows the affected lookup paths and the fix consistently snapshots hash pointers and hmask before RCU traversal.

## 4. Severity interpretation

This behaves like an actionable Moderate issue rather than an ordinary low-risk DoS. The concrete primitive is an OOB read and possible invalid hlist traversal, not an OOB write or demonstrated privilege-escalation primitive.

The realistic impact is kernel crash / DoS under a race. The theoretical concern is that an RCU lookup over an out-of-bounds bucket could misinterpret adjacent kernel memory as list metadata, but the patch does not show attacker-controlled overwrite, reclaim, callback dispatch, or a direct LPE primitive. Therefore it should not be treated as a strong Important candidate, but it should also not be auto-closed without manual review.

## 5. One-sentence report phrase

An XFRM state lookup can race with hash table resize and use an hmask that does not match the published hlist array, causing an out-of-bounds read and possible kernel crash, with practical triggering usually requiring local CAP_NET_ADMIN or delegated network namespace control.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: this is a race and RCU issue in a networking security path with an out-of-bounds read during hash-table traversal. No strong LPE primitive is demonstrated, but the combination of OOB access, RCU traversal, and namespace-dependent reachability warrants manual triage.

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

Patch: xfrm: state: fix out-of-bounds read during lookup [ Upstream
Commit: a16871c7832ea6435abb6e0b58289ae7dcb7e4fc
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a16871c7832ea6435abb6e0b58289ae7dcb7e4fc

Changed files:
  net/xfrm/xfrm_state.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=a16871c7832ea6435abb6e0b58289ae7dcb7e4fc

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

The original Linux kernel CVE announcement for CVE-2024-57982 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2024-57982

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:H/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS score: 5.8

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: 2
  Paranoid ActionableScore: 5

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: NO
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).