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CVE Record

CVE-2025-68776: net/hsr: fix NULL pointer dereference in prp_get_untagged_frame()

In the Linux kernel, the following vulnerability has been resolved: net/hsr: fix NULL pointer dereference in prp_get_untagged_frame() prp_get_untagged_frame() calls __pskb_copy() to create frame->skb_std but doesn't check if the allocation failed. If __pskb_copy() returns NULL, skb_clone() is called with a NULL pointer, causing a crash: Oops: general protection fault, probably for non-canonical address 0xdffffc000000000f: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000078-0x000000000000007f] CPU: 0 UID: 0 PID: 5625 Comm: syz.1.18 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:skb_clone+0xd7/0x3a0 net/core/skbuff.c:2041 Code: 03 42 80 3c 20 00 74 08 4c 89 f7 e8 23 29 05 f9 49 83 3e 00 0f 85 a0 01 00 00 e8 94 dd 9d f8 48 8d 6b 7e 49 89 ee 49 c1 ee 03 <43> 0f b6 04 26 84 c0 0f 85 d1 01 00 00 44 0f b6 7d 00 41 83 e7 0c RSP: 0018:ffffc9000d00f200 EFLAGS: 00010207 RAX: ffffffff892235a1 RBX: 0000000000000000 RCX: ffff88803372a480 RDX: 0000000000000000 RSI: 0000000000000820 RDI: 0000000000000000 RBP: 000000000000007e R08: ffffffff8f7d0f77 R09: 1ffffffff1efa1ee R10: dffffc0000000000 R11: fffffbfff1efa1ef R12: dffffc0000000000 R13: 0000000000000820 R14: 000000000000000f R15: ffff88805144cc00 FS: 0000555557f6d500(0000) GS:ffff88808d72f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555581d35808 CR3: 000000005040e000 CR4: 0000000000352ef0 Call Trace: <TASK> hsr_forward_do net/hsr/hsr_forward.c:-1 [inline] hsr_forward_skb+0x1013/0x2860 net/hsr/hsr_forward.c:741 hsr_handle_frame+0x6ce/0xa70 net/hsr/hsr_slave.c:84 __netif_receive_skb_core+0x10b9/0x4380 net/core/dev.c:5966 __netif_receive_skb_one_core net/core/dev.c:6077 [inline] __netif_receive_skb+0x72/0x380 net/core/dev.c:6192 netif_receive_skb_internal net/core/dev.c:6278 [inline] netif_receive_skb+0x1cb/0x790 net/core/dev.c:6337 tun_rx_batched+0x1b9/0x730 drivers/net/tun.c:1485 tun_get_user+0x2b65/0x3e90 drivers/net/tun.c:1953 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0449f8e1ff Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48 RSP: 002b:00007ffd7ad94c90 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f044a1e5fa0 RCX: 00007f0449f8e1ff RDX: 000000000000003e RSI: 0000200000000500 RDI: 00000000000000c8 RBP: 00007ffd7ad94d20 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000003e R11: 0000000000000293 R12: 0000000000000001 R13: 00007f044a1e5fa0 R14: 00007f044a1e5fa0 R15: 0000000000000003 </TASK> Add a NULL check immediately after __pskb_copy() to handle allocation failures gracefully.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can crash affected systems when HSR/PRP networking code hits an unhandled memory allocation failure. The supplied evidence supports denial of service, not data theft or remote code execution. Exposure appears most relevant where HSR/PRP redundancy networking is enabled or present in embedded/industrial Linux environments.

Executive priority

Treat as a targeted availability risk. Prioritize patch validation for industrial, embedded, or high-availability Linux systems using HSR/PRP; schedule routine remediation elsewhere unless local exposure is confirmed.

Technical view

prp_get_untagged_frame() calls __pskb_copy() and then skb_clone() without checking whether the copy returned NULL. If allocation fails, skb_clone() dereferences NULL and triggers a kernel crash. The fix adds a NULL check after __pskb_copy().

Likely exposure

Likely limited to Linux kernels using the net/hsr PRP/HSR forwarding path. General Linux hosts not using HSR/PRP networking are less likely exposed, but embedded or industrial systems should verify kernel lineage and vendor advisories.

Exploitation context

The source bundle shows a syzkaller-triggered crash trace and KEV is false. No supplied source states active exploitation, public weaponization, privilege escalation, or code execution.

Researcher notes

Evidence supports a kernel NULL pointer dereference in the PRP untagged-frame path after failed skb copy allocation. The supplied data lacks CVSS, CWE, exploitability analysis, and detailed affected version ranges beyond listed Linux versions and stable fix references.

Mitigation direction

  • Update to a kernel version containing the referenced stable fixes.
  • Check Linux distribution or device-vendor advisories for backported patches.
  • Prioritize systems using HSR/PRP or industrial redundancy networking.
  • If patch status is unclear, follow vendor guidance before assuming mitigation.

Validation and detection

  • Inventory Linux kernel versions and vendor patch levels.
  • Check whether HSR/PRP kernel functionality is enabled or used.
  • Map deployed kernels against the referenced stable commits or vendor advisories.
  • Review crash logs for NULL pointer dereferences in hsr/prp paths.
Prepared
Confidence
medium
Sources
10

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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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
1ADP providers
9Source 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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ADP provider summaries

siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxf266a683a4804dc499efc6c2206ef68efed029d0, f266a683a4804dc499efc6c2206ef68efed029d0, f266a683a4804dc499efc6c2206ef68efed029d0, f266a683a4804dc499efc6c2206ef68efed029d0, f266a683a4804dc499efc6c2206ef68efed029d0, f266a683a4804dc499efc6c2206ef68efed029d0, f266a683a4804dc499efc6c2206ef68efed029d0unaffected
LinuxLinux3.17, 0, 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3, 6.19affected
Weakness

CWE details

No CWE listed

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