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

> A missing length check in the Qualcomm rmnet driver allows out-of-bounds reads, potentially causing crashes or code execution when ingress deaggregation is disabled.

- **Severity:** High 7.3 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Jul 2026
- **Updated:** 17 Aug 2026
- **Also known as:** AZL-94055, BELL-CVE-2026-64550, DEBIAN-CVE-2026-64550, GHSA-wpm4-rcr2-x634, ROOT-OS-DEBIAN-12-CVE-2026-64550, UBUNTU-CVE-2026-64550

## What is CVE-2026-64550?

CVE-2026-64550 is a high-severity memory corruption vulnerability in Linux, published on 27 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

## Which versions are affected by CVE-2026-64550?


## How do I fix CVE-2026-64550?

Apply the vendor's patch.

## Is CVE-2026-64550 being exploited?

There is no known exploitation of CVE-2026-64550 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64550 and fix it if it is affected.

What it is: CVE-2026-64550 is a high-severity memory corruption vulnerability in Linux, published on 27 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-64550 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-64550/ (Markdown: https://insights.sbomify.com/CVE-2026-64550/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64550
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64550
- OSV: https://osv.dev/vulnerability/CVE-2026-64550

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64550/
Summaries are generated and may contain mistakes; the official description above is the record.