The AlmaLinux 9.6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.6:CLSA-2026:1778863931 advisory.

  - In the Linux kernel, the following vulnerability has been resolved: net: skbuff: propagate shared-frag     marker through frag-transfer helpers Two frag-transfer helpers (__pskb_copy_fclone() and skb_shift()) fail     to propagate the SKBFL_SHARED_FRAG bit in skb_shinfo()->flags when moving frags from source to     destination. __pskb_copy_fclone() defers the rest of the shinfo metadata to skb_copy_header() after     copying frag descriptors, but that helper only carries over gso_{size,segs, type} and never touches     skb_shinfo()->flags; skb_shift() moves frag descriptors directly and leaves flags untouched. As a result,     the destination skb keeps a reference to the same externally-owned or page-cache-backed pages while     reporting skb_has_shared_frag() as false. The mismatch is harmful in any in-place writer that uses     skb_has_shared_frag() to decide whether shared pages must be detoured through skb_cow_data(). ESP input is     one such writer (esp4.c, esp6.c), and a single nft 'dup to <local>' rule -- or any other nf_dup_ipv4() /     xt_TEE caller -- is enough to land a pskb_copy()'d skb in esp_input() with the marker stripped, letting an     unprivileged user write into the page cache of a root-owned read-only file via authencesn-ESN stray     writes. Set SKBFL_SHARED_FRAG on the destination whenever frag descriptors were actually moved from the     source. skb_copy() and skb_copy_expand() share skb_copy_header() too but linearize all paged data into     freshly allocated head storage and emerge with nr_frags == 0, so skb_has_shared_frag() returns false on     its own; they need no change. The same omission exists in skb_gro_receive() and skb_gro_receive_list().
    The former moves the incoming skb's frag descriptors into the accumulator's last sub-skb via two paths (a     direct frag-move loop and the head_frag + memcpy path); the latter chains the incoming skb whole onto p's     frag_list. Downstream skb_segment() reads only skb_shinfo(p)->flags, and skb_segment_list() reuses each     sub-skb's shinfo as the nskb -- both p and lp must carry the marker. The same omission also exists in     tcp_clone_payload(), which builds an MTU probe skb by moving frag descriptors from skbs on sk_write_queue     into a freshly allocated nskb. The helper falls into the same family and warrants the same fix for     consistency; no TCP TX-side in-place writer is currently known to reach a user page through this gap, but     a future consumer depending on the marker would regress silently. The same omission exists in     skb_segment(): the per-iteration flag merge takes only head_skb's flag, and the inner switch that rebinds     frag_skb to list_skb on head_skb-frags exhaustion does not fold the new frag_skb's flag into nskb. Fold     frag_skb's flag at both sites so segments drawing frags from frag_list members carry the marker.
    (CVE-2026-43503)

  - In the Linux kernel, the following vulnerability has been resolved: net: skbuff: preserve shared-frag     marker during coalescing skb_try_coalesce() can attach paged frags from @from to @to. If @from has     SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same externally-owned or page-cache-backed     frags, but the shared-frag marker is currently lost. That breaks the invariant relied on by later in-place     writers. In particular, ESP input checks skb_has_shared_frag() before deciding whether an uncloned     nonlinear skb can skip skb_cow_data(). If TCP receive coalescing has moved shared frags into an unmarked     skb, ESP can see skb_has_shared_frag() as false and decrypt in place over page-cache backed frags.
    Propagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged frags. The tailroom copy path does not     need the marker because it copies bytes into @to's linear data rather than transferring frag descriptors.
    (CVE-2026-46300)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

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AlmaLinux 9.6 [TuxCare] Security Update: kernel / kernel-abi-stablelists / kernel-core / etc Multiple Vulnerabilities (ALMALINUX9.6:CLSA-2026:1778863931)

high Nessus Plugin ID 360839

Version 1.4