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AlmaLinux 9.2 [TuxCare] 安全性更新：bpftool / kernel / kernel-abi-stablelists / kernel-core / etc多個弱點 （ALMALINUX9.2：CLSA-2026：1778867412）

high Nessus Plugin ID 360766

語言:

概要

AlmaLinux 主機缺少一或多個安全性更新。

說明

AlmaLinux 9.2 主機已安裝的套件會受到 TuxCare ALMALINUX9.2：CLSA-2026：1778867412 公告中提及的多個弱點影響。

 - 已解決 Linux 核心中的下列弱點：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)

 - 已解決 Linux 核心中的下列弱點：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)

請注意，Nessus 並未測試這些問題，而是僅依據應用程式自我報告的版本號碼作出判斷。

解決方案

根據 TuxCare 公告 ALMALINUX9.2：CLSA-2026：1778867412 中的指引更新受影響的套件。

另請參閱

https://cve.tuxcare.com/els/releases/CLSA-2026:1778867412

http://www.nessus.org/u?1161ef9d

Plugin 詳細資訊

嚴重性: High

ID: 360766

檔案名稱: tuxcare_alma_linux_9.2_CLSA-2026-1778867412.nasl

版本: 1.2

類型: Local

已發布: 2026/10/1

已更新: 2026/10/2

支援的感應器: Continuous Assessment, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

風險資訊

VPR

風險因素: Critical

分數: 9.5

百分位數: 99.87

Vendor

Vendor Severity: Important

CVSS v2

風險因素: Medium

基本分數: 6.8

時間性分數: 5.9

媒介: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C

CVSS 評分資料來源: CVE-2026-46300

CVSS v3

風險因素: High

基本分數: 7.8

時間性分數: 7.5

媒介: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

時間媒介: CVSS:3.0/E:H/RL:O/RC:C

弱點資訊

必要的 KB 項目: Host/OS/extended-third-party, Host/local_checks_enabled, Host/AlmaLinux/release, Host/AlmaLinux/rpm-list, Host/cpu

可被惡意程式利用: true

可輕鬆利用: Exploits are available

修補程式發佈日期: 2026/5/15

弱點發布日期: 2026/5/13

可惡意利用

Core Impact

Metasploit (Sample Linux Priv Esc, DescriptionThis exploit module illustrates how a vulnerability could be exploitedin an linux command for priv esc.})

參考資訊

CVE: CVE-2026-43503, CVE-2026-46300

CLSA: 2026:1778867412