# CVE-2026-99056: strparser: make sure __strp_recv isn't running before tearing down the parser

CVE-2026-99056 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-99056, released October 24, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-99056
- Priority: High
- CVSS: 7.8 (Important)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 23, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99056

## Description

In the Linux kernel, the following vulnerability has been resolved:  strparser: make sure __strp_recv isn't running before tearing down the parser  The comment above strp_done() claims that if strp is stopped, strp_recv will no longer be called. That's only true if the caller has a mechanism (eg locking) to guarantee that strp_recv() calls that started before strp_stop() have completed by the time we call strp_done().  This adds a dummy lock_sock/release_sock pair to guarantee that any in-flight strp_recv() (which runs under either bh_lock_sock or lock_sock, depending if it's called from ->sk_data_ready or strp_work) has completed.  Only espintcp can be affected by this race condition, but this patch makes sure no future user of strp can have the bug.  This could crash on strp->sk ("general mode" of strp), but this mode has been here for 9 years and has never been used. It'll be gone soon, no point worrying about it.  Switch the stopped/paused/etc bits to u8's to avoid races between strp_stop() and strp_pause/unpause().  A reproducer has been published and turns the possible UAF into an exploit [1].

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.113-1 | [DEBIAN-CVE-2026-99056](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99056.md) | Oct 24, 2026 |
| Linux | linux Debian 14 | 7.2.11-1 | [DEBIAN-CVE-2026-99056](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99056.md) | Oct 24, 2026 |

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Data as of 2026-11-09T13:31:49Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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