NVD / CVE Program· CNA Linux

CVE-2025-38666: net: appletalk: Fix use-after-free in AARP proxy probe

Noroxi assessment

Priority: Monitor (action score 31/100)

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: 0.17% (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 186942d19c0222617ef61f50e1dba91e269a5963, 2a6209e4649d45fd85d4193abc481911858ffc6f, 5f02ea0f63dd38c41539ea290fcc1693c73aa8e5; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1.

Low priority for now. Upgrade to Linux Linux 186942d19c0222617ef61f50e1dba91e269a5963, 2a6209e4649d45fd85d4193abc481911858ffc6f, 5f02ea0f63dd38c41539ea290fcc1693c73aa8e5; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1 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: net: appletalk: Fix use-after-free in AARP proxy probe The AARP proxy‐probe routine (aarp_proxy_probe_network) sends a probe, releases the aarp_lock, sleeps, then re-acquires the lock. During that window an expire timer thread (__aarp_expire_timer) can remove and kfree() the same entry, leading to a use-after-free. race condition: cpu 0 | cpu 1 atalk_sendmsg() | atif_proxy_probe_device() aarp_send_ddp() | aarp_proxy_probe_network() mod_timer() | lock(aarp_lock) // LOCK!! timeout around 200ms | alloc(aarp_entry) and then call | proxies[hash] = aarp_entry aarp_expire_timeout() | aarp_send_probe() | unlock(aarp_lock) // UNLOCK!! lock(aarp_lock) // LOCK!! | msleep(100); __aarp_expire_timer(&proxies[ct]) | free(aarp_entry) | unlock(aarp_lock) // UNLOCK!! | | lock(aarp_lock) // LOCK!! | UAF aarp_entry !! ================================================================== BUG: KASAN: slab-use-after-free in aarp_proxy_probe_network+0x560/0x630 net/appletalk/aarp.c:493 Read of size 4 at addr ffff8880123aa360 by task repro/13278 CPU: 3 UID: 0 PID: 13278 Comm: repro Not tainted 6.15.2 #3 PREEMPT(full) Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xc1/0x630 mm/kasan/report.c:521 kasan_report+0xca/0x100 mm/kasan/report.c:634 aarp_proxy_probe_network+0x560/0x630 net/appletalk/aarp.c:493 atif_proxy_probe_device net/appletalk/ddp.c:332 [inline] atif_ioctl+0xb58/0x16c0 net/appletalk/ddp.c:857 atalk_ioctl+0x198/0x2f0 net/appletalk/ddp.c:1818 sock_do_ioctl+0xdc/0x260 net/socket.c:1190 sock_ioctl+0x239/0x6a0 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x194/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcb/0x250 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Allocated: aarp_alloc net/appletalk/aarp.c:382 [inline] aarp_proxy_probe_network+0xd8/0x630 net/appletalk/aarp.c:468 atif_proxy_probe_device net/appletalk/ddp.c:332 [inline] atif_ioctl+0xb58/0x16c0 net/appletalk/ddp.c:857 atalk_ioctl+0x198/0x2f0 net/appletalk/ddp.c:1818 Freed: kfree+0x148/0x4d0 mm/slub.c:4841 __aarp_expire net/appletalk/aarp.c:90 [inline] __aarp_expire_timer net/appletalk/aarp.c:261 [inline] aarp_expire_timeout+0x480/0x6e0 net/appletalk/aarp.c:317 The buggy address belongs to the object at ffff8880123aa300 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 96 bytes inside of freed 192-byte region [ffff8880123aa300, ffff8880123aa3c0) Memory state around the buggy address: ffff8880123aa200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880123aa280: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880123aa300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880123aa380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8880123aa400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================

HighCVSS 7.8 · v3.1—No exploit Fix available

BDU:2025-15186

Published: Aug 22, 2025
Updated: Jun 17, 2026
EPSS: 0.1% · 6th percentile
CWE: CWE-416

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

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No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

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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.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel
debian	debian linux	cpe:2.3:o:debian:debian_linux

Affected versions

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

debian debian linux11.0
linux linux kernel5.5 and later · before 5.10.241
linux linux kernel5.11 and later · before 5.15.190
linux linux kernel5.16 and later · before 6.1.148
linux linux kernel6.2 and later · before 6.6.101
linux linux kernel2.6.13 and later · before 5.4.297
linux linux kernel6.13 and later · before 6.15.9
linux linux kernel6.7 and later · before 6.12.41
linux linux kernel2.6.12
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
- 2.6.12affected
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before b35694ffabb2af308a1f725d70f60fd8a47d1f3eaffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 82d19a70ced28b17a38ebf1b6978c6c7db894979affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 186942d19c0222617ef61f50e1dba91e269a5963affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 2a6209e4649d45fd85d4193abc481911858ffc6faffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e4f1564c5b699eb89b3040688fd6b4e57922f1f6affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 5f02ea0f63dd38c41539ea290fcc1693c73aa8e5affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before f90b6bb203f3f38bf2b3d976113d51571df9a482affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 6c4a92d07b0850342d3becf2e608f805e972467caffected · git
- before 2.6.12not affected · semver

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.148-1	6.1.148-1
Debian:13	linux	before 6.12.41-1	6.12.41-1
Debian:14	linux	before 6.16.3-1	6.16.3-1

Same product

linux: all records

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Published before and after this one in the same product

← EarlierCVE-2025-38662Aug 22, 2025 · ASoC: mediatek: mt8365-dai-i2s: pass correct size to mt8365_dai_set_priv
31Monitor
← EarlierCVE-2025-38663Aug 22, 2025 · nilfs2: reject invalid file types when reading inodes
22Monitor
Later →CVE-2025-38667Aug 22, 2025 · iio: fix potential out-of-bound write
31Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
Linux Linux	186942d19c0222617ef61f50e1dba91e269a5963	Vendor (CNA)
Linux Linux	2a6209e4649d45fd85d4193abc481911858ffc6f	Vendor (CNA)
Linux Linux	5f02ea0f63dd38c41539ea290fcc1693c73aa8e5	Vendor (CNA)
Linux Linux	6c4a92d07b0850342d3becf2e608f805e972467c	Vendor (CNA)
Linux Linux	82d19a70ced28b17a38ebf1b6978c6c7db894979	Vendor (CNA)
Linux Linux	b35694ffabb2af308a1f725d70f60fd8a47d1f3e	Vendor (CNA)
Linux Linux	e4f1564c5b699eb89b3040688fd6b4e57922f1f6	Vendor (CNA)
Linux Linux	f90b6bb203f3f38bf2b3d976113d51571df9a482	Vendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.0	6.6.104.2-1 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0	5.15.200.1-1 · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.148-1 · Debian:12	Package 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.

No history yet (it accumulates with the daily EPSS job).

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.

No nightly-computed relations.

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: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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

Fix✗ → ✓Sep 28, 2026, 10:10 PM UTC

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

References

git.kernel.org/stable/c/186942d19c0222617ef61f50e1dba91e269a5963

Show all references (9 more)

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

All records