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NVD / CVE Program· CNA Linux

CVE-2025-38544: rxrpc: Fix bug due to prealloc collision

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.15% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 432c5363cd6fe5a928bbc94524d28b05515684dd, 5385ad53793de2ab11e396bdcdaa65bb04b4dad6, 69e4186773c6445b258fb45b6e1df18df831ec45; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 432c5363cd6fe5a928bbc94524d28b05515684dd, 5385ad53793de2ab11e396bdcdaa65bb04b4dad6, 69e4186773c6445b258fb45b6e1df18df831ec45; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix bug due to prealloc collision When userspace is using AF_RXRPC to provide a server, it has to preallocate incoming calls and assign to them call IDs that will be used to thread related recvmsg() and sendmsg() together. The preallocated call IDs will automatically be attached to calls as they come in until the pool is empty. To the kernel, the call IDs are just arbitrary numbers, but userspace can use the call ID to hold a pointer to prepared structs. In any case, the user isn't permitted to create two calls with the same call ID (call IDs become available again when the call ends) and EBADSLT should result from sendmsg() if an attempt is made to preallocate a call with an in-use call ID. However, the cleanup in the error handling will trigger both assertions in rxrpc_cleanup_call() because the call isn't marked complete and isn't marked as having been released. Fix this by setting the call state in rxrpc_service_prealloc_one() and then marking it as being released before calling the cleanup function.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Aug 16, 2025
Updated
Jun 17, 2026
EPSS
0.1% · 4th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel4.9 and later · before 6.6.99
  • linux linux kernel6.7 and later · before 6.12.39
  • linux linux kernel6.13 and later · before 6.15.7
  • linux linux kernel6.16

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.9affected
    • 00e907127e6f86d0f9b122d9b4347a8aa09a8b61 and later · before 432c5363cd6fe5a928bbc94524d28b05515684ddaffected · git
    • 00e907127e6f86d0f9b122d9b4347a8aa09a8b61 and later · before 5385ad53793de2ab11e396bdcdaa65bb04b4dad6affected · git
    • 00e907127e6f86d0f9b122d9b4347a8aa09a8b61 and later · before d8ffb47a443919277cb093c3db1ec6c0a06880b1affected · git
    • 00e907127e6f86d0f9b122d9b4347a8aa09a8b61 and later · before 69e4186773c6445b258fb45b6e1df18df831ec45affected · git
    • before 4.9not affected · semver
    • 6.6.99 and later · up to and including 6.6.*not affected · semver
    • 6.12.39 and later · up to and including 6.12.*not affected · semver
    • 6.15.7 and later · up to and including 6.15.*not affected · semver
    • 6.16 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.41-16.12.41-1
Debian:14linuxbefore 6.16.3-16.16.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-38542Aug 16, 2025 · net: appletalk: Fix device refcount leak in atrtr_create()
    22Monitor
  • ← EarlierCVE-2025-38543Aug 16, 2025 · drm/tegra: nvdec: Fix dma_alloc_coherent error check
    22Monitor
  • Later →CVE-2025-38545Aug 16, 2025 · net: ethernet: ti: am65-cpsw-nuss: Fix skb size by accounting for skb_shared_info
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux432c5363cd6fe5a928bbc94524d28b05515684ddVendor (CNA)
Linux Linux5385ad53793de2ab11e396bdcdaa65bb04b4dad6Vendor (CNA)
Linux Linux69e4186773c6445b258fb45b6e1df18df831ec45Vendor (CNA)
Linux Linuxd8ffb47a443919277cb093c3db1ec6c0a06880b1Vendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0Release NotesMicrosoft (MSRC)
debian:linux6.12.41-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-31739258 days apartcrypto: tegra - Add missing CRYPTO_ALG_ASYNC
    35Monitor
  • CVE-2026-52952312 days apartiommu: Fix WARN_ON in __iommu_group_set_domain_nofail() due to reset
    35Monitor
  • CVE-2025-3980330 days apartscsi: ufs: core: Remove WARN_ON_ONCE() call from ufshcd_uic_cmd_compl()
    31Monitor
  • CVE-2026-31398230 days apartmm/rmap: fix incorrect pte restoration for lazyfree folios
    31Monitor
  • CVE-2026-46117285 days apartRDMA/mana: Remove user triggerable WARN_ON() in mana_ib_create_qp_rss()
    31Monitor
  • CVE-2023-52621508 days apartbpf: Check rcu_read_lock_trace_held() before calling bpf map helpers
    31Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-617 · Reachable Assertion

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records