ACK: [SRU][Q][PATCH 0/1] CVE-2026-52999

[Benjamin Wheeler]

Acked-by: Benjamin Wheeler <benjamin.wheeler at canonical.com>

On Thu, Jul 16, 2026 at 10:26 AM Cengiz Can via kernel-team <
kernel-team at lists.ubuntu.com> wrote:

> https://ubuntu.com/security/CVE-2026-52999
>
> [ Impact ]
>
> In nf_osf_match(), the nf_osf_hdr_ctx structure is initialized once and
> passed
> by reference to nf_osf_match_one() for each fingerprint checked. During TCP
> option parsing, nf_osf_match_one() advances the shared ctx->optp pointer
> without restoring it after an early return on a perfect match. When
> NF_OSF_LOGLEVEL_ALL is configured, subsequent fingerprint checks start
> parsing
> from the end of the options buffer, causing an out-of-bounds read of
> garbage
> data. This results in incorrect or missing match logging.
>
> [ Fix ]
>
> questing: clean cherry-pick
> focal: clean cherry-pick
>
> [ Test Plan ]
>
> Boot tested.
>
> [ Where Problems Could Occur ]
>
> A regression in the netfilter nfnetlink_osf module could affect OS
> fingerprint
> matching, potentially causing incorrect passive OS detection results or
> breaking connections filtered by osf rules.
>
> --
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team
>
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