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CVE Record

CVE-2025-38589: neighbour: Fix null-ptr-deref in neigh_flush_dev().

In the Linux kernel, the following vulnerability has been resolved: neighbour: Fix null-ptr-deref in neigh_flush_dev(). kernel test robot reported null-ptr-deref in neigh_flush_dev(). [0] The cited commit introduced per-netdev neighbour list and converted neigh_flush_dev() to use it instead of the global hash table. One thing we missed is that neigh_table_clear() calls neigh_ifdown() with NULL dev. Let's restore the hash table iteration. Note that IPv6 module is no longer unloadable, so neigh_table_clear() is called only when IPv6 fails to initialise, which is unlikely to happen. [0]: IPv6: Attempt to unregister permanent protocol 136 IPv6: Attempt to unregister permanent protocol 17 Oops: general protection fault, probably for non-canonical address 0xdffffc00000001a0: 0000 [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000d00-0x0000000000000d07] CPU: 1 UID: 0 PID: 1 Comm: systemd Tainted: G T 6.12.0-rc6-01246-gf7f52738637f #1 Tainted: [T]=RANDSTRUCT Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:neigh_flush_dev.llvm.6395807810224103582+0x52/0x570 Code: c1 e8 03 42 8a 04 38 84 c0 0f 85 15 05 00 00 31 c0 41 83 3e 0a 0f 94 c0 48 8d 1c c3 48 81 c3 f8 0c 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 f7 49 93 fe 4c 8b 3b 4d 85 ff 0f RSP: 0000:ffff88810026f408 EFLAGS: 00010206 RAX: 00000000000001a0 RBX: 0000000000000d00 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffc0631640 RBP: ffff88810026f470 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffffc0625250 R14: ffffffffc0631640 R15: dffffc0000000000 FS: 00007f575cb83940(0000) GS:ffff8883aee00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f575db40008 CR3: 00000002bf936000 CR4: 00000000000406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __neigh_ifdown.llvm.6395807810224103582+0x44/0x390 neigh_table_clear+0xb1/0x268 ndisc_cleanup+0x21/0x38 [ipv6] init_module+0x2f5/0x468 [ipv6] do_one_initcall+0x1ba/0x628 do_init_module+0x21a/0x530 load_module+0x2550/0x2ea0 __se_sys_finit_module+0x3d2/0x620 __x64_sys_finit_module+0x76/0x88 x64_sys_call+0x7ff/0xde8 do_syscall_64+0xfb/0x1e8 entry_SYSCALL_64_after_hwframe+0x67/0x6f RIP: 0033:0x7f575d6f2719 Code: 08 89 e8 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b7 06 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007fff82a2a268 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 RAX: ffffffffffffffda RBX: 0000557827b45310 RCX: 00007f575d6f2719 RDX: 0000000000000000 RSI: 00007f575d584efd RDI: 0000000000000004 RBP: 00007f575d584efd R08: 0000000000000000 R09: 0000557827b47b00 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000020000 R13: 0000000000000000 R14: 0000557827b470e0 R15: 00007f575dbb4270 </TASK> Modules linked in: ipv6(+)

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

CVE-2025-38589 is a Linux kernel crash bug in neighbor-table cleanup. The available source describes a null pointer dereference found by automated testing, in an unlikely IPv6 initialization failure path. There is no cited evidence of active exploitation or business-impacting attacks.

Executive priority

Schedule normal kernel patching through existing maintenance windows. Escalate only if affected kernels run on critical systems showing IPv6 initialization failures or unexplained kernel crashes.

Technical view

A prior Linux kernel change moved neighbor flushing to per-netdev lists. neigh_table_clear() can call neigh_ifdown() with a NULL device, but neigh_flush_dev() did not handle that path, causing a null pointer dereference. The fix restores hash-table iteration for this cleanup case.

Likely exposure

Exposure appears limited to affected Linux kernel versions or builds containing the cited regression. The described crash path is tied to IPv6 cleanup during failed initialization, which the source says is unlikely.

Exploitation context

The source bundle provides no exploit code, public exploitation report, KEV listing, CVSS vector, or remote trigger details. Treat this as a reliability and availability issue unless vendor guidance says otherwise.

Researcher notes

The evidence is narrow: automated test crash, null device path, and upstream stable fixes. No CWE, CVSS, or exploitability assessment is provided. The upstream note says IPv6 is no longer unloadable and the vulnerable path is unlikely.

Mitigation direction

  • Apply the relevant Linux stable kernel update containing the referenced fix.
  • Check distribution vendor advisories for backported kernel packages.
  • Prioritize systems running affected kernel lines with custom or unstable IPv6/module configurations.
  • Avoid assuming exploitability beyond the documented crash condition.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and containers with host kernel dependency.
  • Compare deployed kernels against vendor-fixed packages or referenced stable commits.
  • Review boot and kernel logs for IPv6 initialization failures or neighbor cleanup crashes.
  • Confirm patch status through distribution package metadata, not only upstream version strings.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2025-38589 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
4Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxf7f52738637f4361c108cad36e23ee98959a9006, f7f52738637f4361c108cad36e23ee98959a9006, f7f52738637f4361c108cad36e23ee98959a9006unaffected
LinuxLinux6.13, 0, 6.15.10, 6.16.1, 6.17affected
Weakness

CWE details

No CWE listed

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