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CVE-2026-74621: Linux

7.5

CVSS 3.1

Няма данни

Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

Няма потвърждение

Атакува се

Няма данни

Време до експлоатация

Атакува се по мрежата, без особени условия, без вход и без действие от потребителя.

  • Експлоатация: няма данни за експлоатация
  • Атаката може да се автоматизира

Описание

Оригинално описание

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_ct: fix sk_buff leak when the header checks reject a packet tcf_ct_handle_fragments() runs its header sanity checks before handing anything to the defragmentation engine: if (family == NFPROTO_IPV4) err = tcf_ct_ipv4_is_fragment(skb, &frag); else err = tcf_ct_ipv6_is_fragment(skb, &frag); if (err || !frag) return err; tcf_ct_ipv4_is_fragment() returns -EINVAL or -ENOMEM; tcf_ct_ipv6_is_fragment() adds -EPROTO when ipv6_find_hdr() fails. None of them frees or queues the skb, so on that path the caller still owns it. tcf_ct_act() however funnels every non-zero return into the ownership-transfer exit: err = tcf_ct_handle_fragments(net, skb, family, p->zone, &defrag); if (err) goto out_frag; ... out_frag: if (err != -EINPROGRESS) tcf_action_inc_drop_qstats(&c->common); return TC_ACT_CONSUMED; TC_ACT_CONSUMED means the action took ownership of the skb, so no caller frees it - sch_handle_ingress(), sch_handle_egress() and tcf_qevent_handle() all deliberately skip the free for that verdict. The skb is therefore orphaned: one sk_buff plus its data buffer is leaked per malformed packet, unbounded. Note the drop counter is already incremented for these errors, so the statistics claim a drop that never happens. Three different ownership states reach out_frag: today - the skb may be queued by the defrag engine (-EINPROGRESS), already freed by nf_ct_handle_fragments(), or still owned by us. Tell the caller which of those it is, and free the packet ourselves in the last case, which restores the TC_ACT_SHOT behaviour that predated the Fixes: commit. Reproduced on v7.2-rc6 with a 54-byte frame carrying a 40-byte IPv6 header with nexthdr = 0 (hop-by-hop) and nothing after it, on a clsact ingress chain with "action ct". kmemleak reports one leaked 232-byte skbuff_head_cache object plus its 704-byte data buffer per packet; with this patch it reports none.

Засегнати продукти

  • Linux Linux: 172ba7d46c202e679f3ccb10264c67416aaeb1c4 преди b5dbecc2016e1692fd1c2532af9c41ba729cb747; 0b5b831122fc3789fff75be433ba3e4dd7b779d4 преди 23e97d594ddd0153020c506d5041048fbde1beb4; 73f7da5fd124f2cda9161e2e46114915e6e82e97 преди 737873a59905a54ca0d2d127ef882f3f88bf4379; 3f14b377d01d8357eba032b4cabc8c1149b458b6 преди 47d99828591d0fe8be4b9c8992ff3b8e47968db9; 3f14b377d01d8357eba032b4cabc8c1149b458b6 преди b47bb899e04b5407c5a63fe88d4b6676586a6e84; 3f14b377d01d8357eba032b4cabc8c1149b458b6 преди 439d3e404f9d5e515911cc8132cde198b337c19e; 3f14b377d01d8357eba032b4cabc8c1149b458b6 преди 8a7ed561671aa6a911a2de99e59ef670a4d0b1df; f5346df0591d10bc948761ca854b1fae6d2ef441; 5.15.148 преди 5.15.217; 6.1.75 преди 6.1.184; 6.6.14 преди 6.6.152; 6.7.2 преди 6.8
  • Linux Linux: 6.8; преди 6.8; 5.15.217 до 5.15.*; 6.1.184 до 6.1.*; 6.6.152 до 6.6.*; 6.12.104 до 6.12.*; 6.18.45 до 6.18.*; 7.1.9 до 7.1.*; 7.2 до *

История

  • 22 август 2026 Публикувано

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Първоизточници

CVE-2026-74621: Linux | freedomonline.bg