medium CVSS 5.5

CVE-2025-21890·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: idpf: fix checksums set in idpf_rx_rsc() idpf_rx_rsc() uses skb_transport_offset(skb) while the transport header is not set yet. This triggers the following warning for CONFIG_DEBUG_NET=y builds. DEBUG_NET_WARN_ON_ONCE(!skb_transport_header_was_set(skb)) [ 69.261620] WARNING: CPU: 7 PID: 0 at ./include/linux/skbuff.h:3020 idpf_vport_splitq_napi_poll (include/linux/skbuff.h:3020) idpf [ 69.261629] Modules linked in: vfat fat dummy bridge intel_uncore_frequency_tpmi intel_uncore_frequency_common intel_vsec_tpmi idpf intel_vsec cdc_ncm cdc_eem cdc_ether usbnet mii xhci_pci xhci_hcd ehci_pci ehci_hcd libeth [ 69.261644] CPU: 7 UID: 0 PID: 0 Comm: swapper/7 Tainted: G S W 6.14.0-smp-DEV #1697 [ 69.261648] Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN [ 69.261650] RIP: 0010:idpf_vport_splitq_napi_poll (include/linux/skbuff.h:3020) idpf [ 69.261677] ? __warn (kernel/panic.c:242 kernel/panic.c:748) [ 69.261682] ? idpf_vport_splitq_napi_poll (include/linux/skbuff.h:3020) idpf [ 69.261687] ? report_bug (lib/bug.c:?) [ 69.261690] ? handle_bug (arch/x86/kernel/traps.c:285) [ 69.261694] ? exc_invalid_op (arch/x86/kernel/traps.c:309) [ 69.261697] ? asm_exc_invalid_op (arch/x86/include/asm/idtentry.h:621) [ 69.261700] ? __pfx_idpf_vport_splitq_napi_poll (drivers/net/ethernet/intel/idpf/idpf_txrx.c:4011) idpf [ 69.261704] ? idpf_vport_splitq_napi_poll (include/linux/skbuff.h:3020) idpf [ 69.261708] ? idpf_vport_splitq_napi_poll (drivers/net/ethernet/intel/idpf/idpf_txrx.c:3072) idpf [ 69.261712] __napi_poll (net/core/dev.c:7194) [ 69.261716] net_rx_action (net/core/dev.c:7265) [ 69.261718] ? __qdisc_run (net/sched/sch_generic.c:293) [ 69.261721] ? sched_clock (arch/x86/include/asm/preempt.h:84 arch/x86/kernel/tsc.c:288) [ 69.261726] handle_softirqs (kernel/softirq.c:561)

Severity
medium
Software
Kernel
Fixed in
6.13.6
Published
2025-03-27

Affected versions

From: 6.13

Until: 6.13.6

Fixed in: 6.13.6

How to fix this CVE

Update your Linux kernel to version 6.13.6 or later to resolve a transport header initialization issue in the idpf driver. This vulnerability affects kernel versions 6.13 through 6.13.5 and causes debug warnings when CONFIG_DEBUG_NET is enabled. Apply the kernel update immediately to prevent potential stability issues in network receive processing.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Check installed kernel version: uname -r
  2. Verify if idpf driver is loaded: lsmod | grep idpf
  3. Check for CONFIG_DEBUG_NET enabled: grep CONFIG_DEBUG_NET /boot/config-$(uname -r)
  4. Search kernel logs for idpf_vport_splitq_napi_poll warnings: dmesg | grep 'idpf_vport_splitq_napi_poll' or journalctl -k | grep 'idpf_vport_splitq_napi_poll'
  5. Confirm kernel patched version: uname -r should show 6.13.6 or later

FAQ

What is CVE-2025-21890?

CVE-2025-21890 is a medium-severity vulnerability in the Linux kernel's idpf (Intel Data Plane Development Kit) driver where the transport header offset is accessed before the transport header is properly initialized, triggering debug warnings and potential stability issues in network packet processing.

Is CVE-2025-21890 being actively exploited?

No, CVE-2025-21890 is not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog and no public exploits are currently available. This is primarily a stability and debug-mode issue rather than a remote execution risk.

What versions of Kernel are affected by CVE-2025-21890?

Linux kernel versions 6.13 through 6.13.5 are affected. Kernel 6.13.6 and later contain the fix.

How do I check if my server is vulnerable to CVE-2025-21890?

Run 'uname -r' to check your kernel version. If it shows 6.13 through 6.13.5 and 'lsmod | grep idpf' shows the idpf driver is loaded, your system is vulnerable.

Does Defensia detect CVE-2025-21890?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2025-21890 will appear in your dashboard with remediation steps.

Related Kernel CVEs

CVE-2026-100075CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters When srpt_alloc_rw_ctxs() fails partway through a multi-buffer indirect descriptor, the unwind path destroys RDMA contexts but leaves stale n_rw_ctx and n_rdma values (and a dangling rw_ctxs pointer). Later sq_wr_avail accounting in srpt_queue_response() or srpt_write_pending() can then subtract the wrong number of send queue credits. Reset the counters and clear rw_ctxs after freeing the heap allocation before returning an error.
CVE-2026-64387CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix query directory replay double-free A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_query_directory_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.
CVE-2026-53176CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN In drivers/infiniband/ulp/isert/ib_isert.c, isert_login_recv_done() computes the login request payload length as wc->byte_len minus ISER_HEADERS_LEN with no lower bound, and login_req_len is a signed int. A remote iSER initiator can post a login Send work request carrying fewer than ISER_HEADERS_LEN (76) bytes, so the subtraction underflows and login_req_len becomes negative. isert_rx_login_req() then reads that negative length back into a signed int, takes size = min(rx_buflen, MAX_KEY_VALUE_PAIRS), and because the min() is signed it keeps the negative value; the value is then passed as the memcpy() length and sign-extended to a multi-gigabyte size_t. The copy into the 8192-byte login->req_buf runs far out of bounds and faults, crashing the target node. The login phase precedes iSCSI authentication, so no credentials are required to reach this path. Reject any login PDU shorter than ISER_HEADERS_LEN before the subtraction, mirroring the existing early return on a failed work completion, so login_req_len can never go negative. The upper bound was already safe: a posted login buffer cannot deliver more than ISER_RX_PAYLOAD_SIZE, so the difference stays at or below MAX_KEY_VALUE_PAIRS and the existing min() clamps it; only the missing lower bound needs to be added.
CVE-2026-64399CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE The FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the destination file's data via vfs_clone_file_range() with neither the share-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle fp->daccess check that the other write-bearing arms carry. A client can overwrite destination data on a read-only share, or from a handle opened with only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp). FILE_WRITE_ATTRIBUTES-only destination handle overwrote the file's data via the clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix; require FILE_WRITE_DATA since this writes data.
CVE-2026-64385CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_ioctl() replay A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_ioctl_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.

References

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