Answer in brief
CVE-2026-98503 records a Unknown severity vulnerability in packet: use ubuf_info completion for TX_RING packets. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=5cd8d46ea1562be80063f53c7c6a5f40224de623 <e67c455d79fbf709a94965f09a2be6bf4f4ba5fd || >=5cd8d46ea1562be80063f53c7c6a5f40224de623 <eda9bcb721f15a93746a99eabda33d80b86404fd || >=5cd8d46ea1562be80063f53c7c6a5f40224de623 <2a0c9afefc0ecea2cc30ccfbbbc98182a0986191 || >=5cd8d46ea1562be80063f53c7c6a5f40224de623 <9518405613863d0bf0700927a21367f5942cf058 || 67f6fba765ef8cb19089d476e3c367212a2fbdfd || f2a67e68dbaeae7c88e5522873d7b908911f9f77 || >=4.14.86 <4.15 || >=4.19.7 <4.20 | e67c455d79fbf709a94965f09a2be6bf4f4ba5fd, eda9bcb721f15a93746a99eabda33d80b86404fd, 2a0c9afefc0ecea2cc30ccfbbbc98182a0986191, 9518405613863d0bf0700927a21367f5942cf058, 4.15, 4.20 |
| Linux/Linuxgeneric | 4.20 | Not reported |
Published upstream
Oct 18, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 18, 2026
In the Linux kernel, the following vulnerability has been resolved: packet: use ubuf_info completion for TX_RING packets tpacket_snd sends skbs with frags pointing into its ring slots. Slots are released when skb->destructor is called. A call to skb_orphan calls skb->destructor before the skb is freed. This can cause the slot to be reused while still linked into the skb. Switch to standard zerocopy completion (ubuf_info) so the slot is only released once all references to the payload are freed or copied. Restore skb->destructor to standard sock_wfree. The ubuf_info completion callback can be called with a NULL skb, but only from net_zcopy_put and related API, used by zerocopy implementations that hold their own reference on the uarg, such as MSG_ZEROCOPY. This uarg is only ever completed from skb_zcopy_clear, so skb is always set. To prevent userspace from aliasing in-flight state on shared ring slots, allocate tpacket_uarg per packet, rather than per slot. This adds a small allocation to the transmit path. Use standard kmalloc to allow backporting to stable kernels. The uarg holds an sk_wmem_alloc reference, rather than an sk_refcnt reference. packet_free_tx_ring waits on sk_wmem_alloc before freeing the ring pages. Always allocate vec->deferred for tx_ring so page-backed rings also wait on sk_wmem_alloc when skb_copy_ubufs drops page refs before calling tpacket_ubuf_complete. Drop the tx_ring.pg_vec test that tpacket_destruct_skb performed before accessing the slot. The sk_wmem_alloc reference now guarantees that the slot is valid. The test is also not sufficient by itself, as it reads pg_vec without pg_vec_lock, so it can race with packet_set_ring. As a result a slot is released when its payload is copied, which can be before transmission (e.g., in skb_orphan_frags_rx). If copied before skb_tx_timestamp() is called, no slot timestamp is recorded, similar to when skb_orphan() was called early in the datapath before this patch. Revert the now unused previous skb_zcopy_.._nouarg infra. Depends on commit 992cc9f94ca9 ("net/packet: defer vmalloc TX_RING free until skbs finish").
Quoted source text, attributed separately from HOL analysis.