CVE-2026-74620— Linux kernel 安全漏洞
一分钟漏洞结论
影响对象
Linux Linux
利用判断
尚无明确在野利用证据，仍需结合暴露面评估
建议动作
优先检查厂商安全公告和参考链接中的修复版本；无法立即升级时，限制受影响服务暴露并加强监测。
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 5.3版本存在安全漏洞，该漏洞源于net/sched的act_gact和act_police对fallback控制操作缺少范围检查，可能导致用户空间设置TC_ACT_CONSUMED值，从而造成内核内存泄漏及拒绝服务。
可能的 ATT&CK 技术 1 AI
T1499 · Endpoint Denial of Service影响版本矩阵 18
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | 720f22fed81bc6fd1765db7014651b6718887bea< 5f038affdacaffedf6a85a06cf59ec0a852d36a7 |
affected |
720f22fed81bc6fd1765db7014651b6718887bea< efa58aeb6a99028b1fbc3ab2f31ba3a881211ad4 |
affected | ||
720f22fed81bc6fd1765db7014651b6718887bea< 725efc2ab4a40affc4e285a2dc4896d103948a6c |
affected | ||
720f22fed81bc6fd1765db7014651b6718887bea< 6bcb8839aa2d686964a4154650afc4db91e1c514 |
affected | ||
720f22fed81bc6fd1765db7014651b6718887bea< 5344e01179baa37547ab29fd7b8614f83faa190c |
affected | ||
720f22fed81bc6fd1765db7014651b6718887bea< 92f00f1d4d204a428b38e26fce3baee144b6955d |
affected | ||
720f22fed81bc6fd1765db7014651b6718887bea< 2e8df8c9190335475a3b64a159d3efd8cdd1cb73 |
affected | ||
720f22fed81bc6fd1765db7014651b6718887bea< 883b56ae58fe657d8497806c7059646e9ba6dbd0 |
affected | ||
| … +10 条更多 | |||
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一、 漏洞 CVE-2026-74620 基础信息
漏洞信息
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Vulnerability Title
net/sched: act_gact, act_police: range check the fallback control action
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
net/sched: act_gact, act_police: range check the fallback control action
tcf_action_check_ctrlact() range checks the primary control action:
if (!opcode)
ret = action > TC_ACT_VALUE_MAX ? -EINVAL : 0;
TC_ACT_VALUE_MAX is TC_ACT_TRAP, so kernel-internal verdicts above it
cannot be set that way. But act_gact and act_police each carry a second,
independent control action supplied by user space that never reaches that
helper - TCA_GACT_PROB.paction and TCA_POLICE_RESULT. Both only reject
TC_ACT_GOTO_CHAIN, so any other value is stored verbatim and returned
verbatim from the action.
In particular user space can store TC_ACT_CONSUMED, which is
TC_ACT_VALUE_MAX + 1 and is deliberately not part of the UAPI value
range. That verdict tells every caller the action took ownership of the
skb, so nobody frees it: sch_handle_ingress(), sch_handle_egress() and
tcf_qevent_handle() all deliberately skip the free for it. The result is
one leaked sk_buff plus its data buffer per packet traversing the filter,
unbounded, for all traffic on the chain including kernel-generated
packets.
Both are trivially deterministic. act_gact clamps tcfg_pval to >= 1, so
with pval = 1 gact_determ() returns the fallback for every packet.
act_police has no mandatory rate, so rate = 0 leaves tcfp_mtu = ~0 and
tcf_police_mtu_check() always passes.
TC_ACT_CONSUMED was added by commit 720f22fed81b ("net: sched: refactor
reinsert action"), after both goto-chain guards were written:
commit 9469f375ab09 ("net/sched: act_gact: disallow 'goto chain' on
fallback control action") and
commit c08f5ed5d625 ("net/sched: act_police: disallow 'goto chain' on
fallback control action"). Neither guard was widened when the new
verdict appeared.
Factor the existing range test out of tcf_action_check_ctrlact() as
tcf_action_valid() and apply it to both fallbacks. The helper cannot call
tcf_action_check_ctrlact() directly because that also allocates a
goto_chain, which is exactly what these two sites must not do.
Reproduced on v7.2-rc6: kmemleak reports one leaked 232-byte
skbuff_head_cache object plus its 704-byte data buffer per packet. With
this patch both configurations are rejected with -EINVAL and kmemleak
reports none.
来源: CVE Program / CVE List V5
CVSS Information
N/A
来源: CVE Program / CVE List V5
Vulnerability Type
N/A
来源: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 5.3版本存在安全漏洞，该漏洞源于net/sched的act_gact和act_police对fallback控制操作缺少范围检查，可能导致用户空间设置TC_ACT_CONSUMED值，从而造成内核内存泄漏及拒绝服务。
来源: 中国国家信息安全漏洞库 CNNVD
CVSS Information
N/A
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Type
N/A
来源: 中国国家信息安全漏洞库 CNNVD
受影响产品
二、漏洞 CVE-2026-74620 的公开POC
| # | POC 描述 | 源链接 | 神龙链接 |
|---|
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CVE-2026-74620 补丁与修复 (7)
同批安全公告 · Linux · 2026-08-22 · 共 149 条
| CVE-2026-74705 | 10.0 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74612 | 10.0 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74688 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74669 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74662 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74727 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74628 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74608 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74617 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74597 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74616 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74723 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74730 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74611 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74586 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74591 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74587 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74588 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74712 | 9.3 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74665 | 9.1 CRITICAL | Linux kernel 安全漏洞 |
显示前 20 条，共 149 条。 查看全部 → →
IV. Related Vulnerabilities
V. Comments for CVE-2026-74620
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