Answer in brief
CVE-2026-99055 records a Unknown severity vulnerability in tcp: reject net_iov in zerocopy receive mapping hints. 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 | >=9f6b619edf2e85746f261b42ae8f818a59d126f7 <563d3564513496b9ce3b3ba7a5154427554d0f06 || >=9f6b619edf2e85746f261b42ae8f818a59d126f7 <1c7463ac0e99cc91c4eecc1b69a740ef1a619932 || >=9f6b619edf2e85746f261b42ae8f818a59d126f7 <3aa6f536a95eb0617c313ae2eb76fdfa85331f85 || >=9f6b619edf2e85746f261b42ae8f818a59d126f7 <8b1f0af1fd5fd113432233ed8a3862ee7c30a84f | 563d3564513496b9ce3b3ba7a5154427554d0f06, 1c7463ac0e99cc91c4eecc1b69a740ef1a619932, 3aa6f536a95eb0617c313ae2eb76fdfa85331f85, 8b1f0af1fd5fd113432233ed8a3862ee7c30a84f |
| Linux/Linuxgeneric | 6.12 | Not reported |
Published upstream
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 23, 2026
In the Linux kernel, the following vulnerability has been resolved: tcp: reject net_iov in zerocopy receive mapping hints After copying a readable prefix, receive_fallback_to_copy() asks tcp_zerocopy_set_hint_for_skb() where page mapping can resume. If the next skb is unreadable, find_next_mappable_frag() passes its net_iov fragment to can_map_frag(). skb_frag_page() returns NULL for a net_iov, but can_map_frag() dereferences it in PageCompound(). A v7.2 KASAN run on a connected TCP socket with 64 readable bytes followed by a 4096-byte NET_IOV_DMABUF fragment reported: BUG: KASAN: null-ptr-deref in can_map_frag tcp_zerocopy_receive -> can_map_frag Kernel panic - not syncing: KASAN: panic_on_warn set The diagnostic inserted the net_iov directly because the test host has no devmem-capable NIC. Hardware end-to-end reachability remains untested and requires CONFIG_NET_DEVMEM plus a supported DMA-buf-bound RX queue. Reject all net_iov fragments before skb_frag_page(). This covers both DMABUF and IOURING net_iov types while leaving page-backed checks unchanged. With the guard, the same queue copied the readable prefix, returned a 4096-byte skip hint, and completed without a fault.
Quoted source text, attributed separately from HOL analysis.