Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
Linux Linux — ibmvnic: Don't reference skb after sending to VIOS
AV AC PR UI S C I A CVSS EPSS %ile KEV
L L L N U H H H 7.8 .0042 35.2 —
AFFECTED
Product Versions Fixed
Linux 032c5e82847a2214c3196a90f0aeba0ce252de58 – —
Linux 4.5 – 6.1.130
TIMELINE
Dec 29 Reserved by Linux
Mar 12 Published (CNA: Linux)
Jul 30 RESCORED — CVE-2025-21855 (Linux). CVSS 8.6 → 7.8 (NVD).
Description
In the Linux kernel, the following vulnerability has been resolved:
ibmvnic: Don't reference skb after sending to VIOS
Previously, after successfully flushing the xmit buffer to VIOS,
the tx_bytes stat was incremented by the length of the skb.
It is invalid to access the skb memory after sending the buffer to
the VIOS because, at any point after sending, the VIOS can trigger
an interrupt to free this memory. A race between reading skb->len
and freeing the skb is possible (especially during LPM) and will
result in use-after-free:
==================================================================
BUG: KASAN: slab-use-after-free in ibmvnic_xmit+0x75c/0x1808 [ibmvnic]
Read of size 4 at addr c00000024eb48a70 by task hxecom/14495
<...>
Call Trace:
[c000000118f66cf0] [c0000000018cba6c] dump_stack_lvl+0x84/0xe8 (unreliable)
[c000000118f66d20] [c0000000006f0080] print_report+0x1a8/0x7f0
[c000000118f66df0] [c0000000006f08f0] kasan_report+0x128/0x1f8
[c000000118f66f00] [c0000000006f2868] __asan_load4+0xac/0xe0
[c000000118f66f20] [c0080000046eac84] ibmvnic_xmit+0x75c/0x1808 [ibmvnic]
[c000000118f67340] [c0000000014be168] dev_hard_start_xmit+0x150/0x358
<...>
Freed by task 0:
kasan_save_stack+0x34/0x68
kasan_save_track+0x2c/0x50
kasan_save_free_info+0x64/0x108
__kasan_mempool_poison_object+0x148/0x2d4
napi_skb_cache_put+0x5c/0x194
net_tx_action+0x154/0x5b8
handle_softirqs+0x20c/0x60c
do_softirq_own_stack+0x6c/0x88
<...>
The buggy address belongs to the object at c00000024eb48a00 which
belongs to the cache skbuff_head_cache of size 224
==================================================================
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
| December 29, 2024 | Reserved | Reserved by Linux |
| March 12, 2025 | Published | Published (CNA: Linux) |
| July 30, 2026 | RESCORED | RESCORED — CVE-2025-21855 (Linux). CVSS 8.6 → 7.8 (NVD). |
Affected
Affected products and packages — 2 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
| Linux | Linux | — | 032c5e82847a2214c3196a90f0aeba0ce252de58 | — |
| Linux | Linux | — | 4.5 | 6.1.130 |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2025-21855 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.