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CVE-2025-39703

Vulnérabilité critique dans Linux (Linux)

CVSS 9.8 · Critique
EPSS 0.4%
Linux•Linux•Versions : <=6.1.*, 48b491a5cc74333c4a6a82fe21cea42c055a3b0b, <=6.12.*, 6.12.44, <b117c41b00902c1a7e24347c405cb82504aeae0b, <5.13, <=6.16.*, <61009439e4bd8d74e705ee15940760321be91d8a, 6.16.4, <3ae272ab523dd6bdc26e879027ed79feac9dd1b3, 0, 6.17, <acd69b597bd3f76d3b3d322b84082226c00eeaa4, 6.6.103, <7af76e9d18a9fd6f8611b3313c86c190f9b6a5a7, 5.12.9, <=5.10.*, <=6.6.*, 5.15.190, f6442ee08fe66c8e45c4f246531a2aaf4f17a7a7, 5.10.42, <5.10.241, 5.13, 6.1.149, 5.10.241, <=*, <=5.15.*, <8d9bc4a375a1ba05f7dfa0407de8e510ab9bd14d, <b640188b8a6690e685939053c7efdbc7818b5f4e, 4ffd1d4a6b306ff69cbe412d2c54d2dd349ff436

Description

In the Linux kernel, the following vulnerability has been resolved: net, hsr: reject HSR frame if skb can't hold tag Receiving HSR frame with insufficient space to hold HSR tag in the skb can result in a crash (kernel BUG): [ 45.390915] skbuff: skb_under_panic: text:ffffffff86f32cac len:26 put:14 head:ffff888042418000 data:ffff888042417ff4 tail:0xe end:0x180 dev:bridge_slave_1 [ 45.392559] ------------[ cut here ]------------ [ 45.392912] kernel BUG at net/core/skbuff.c:211! [ 45.393276] Oops: invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI [ 45.393809] CPU: 1 UID: 0 PID: 2496 Comm: reproducer Not tainted 6.15.0 #12 PREEMPT(undef) [ 45.394433] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 45.395273] RIP: 0010:skb_panic+0x15b/0x1d0 <snip registers, remove unreliable trace> [ 45.402911] Call Trace: [ 45.403105] <IRQ> [ 45.404470] skb_push+0xcd/0xf0 [ 45.404726] br_dev_queue_push_xmit+0x7c/0x6c0 [ 45.406513] br_forward_finish+0x128/0x260 [ 45.408483] __br_forward+0x42d/0x590 [ 45.409464] maybe_deliver+0x2eb/0x420 [ 45.409763] br_flood+0x174/0x4a0 [ 45.410030] br_handle_frame_finish+0xc7c/0x1bc0 [ 45.411618] br_handle_frame+0xac3/0x1230 [ 45.413674] __netif_receive_skb_core.constprop.0+0x808/0x3df0 [ 45.422966] __netif_receive_skb_one_core+0xb4/0x1f0 [ 45.424478] __netif_receive_skb+0x22/0x170 [ 45.424806] process_backlog+0x242/0x6d0 [ 45.425116] __napi_poll+0xbb/0x630 [ 45.425394] net_rx_action+0x4d1/0xcc0 [ 45.427613] handle_softirqs+0x1a4/0x580 [ 45.427926] do_softirq+0x74/0x90 [ 45.428196] </IRQ> This issue was found by syzkaller. The panic happens in br_dev_queue_push_xmit() once it receives a corrupted skb with ETH header already pushed in linear data. When it attempts the skb_push() call, there's not enough headroom and skb_push() panics. The corrupted skb is put on the queue by HSR layer, which makes a sequence of unintended transformations when it receives a specific corrupted HSR frame (with incomplete TAG). Fix it by dropping and consuming frames that are not long enough to contain both ethernet and hsr headers. Alternative fix would be to check for enough headroom before skb_push() in br_dev_queue_push_xmit(). In the reproducer, this is injected via AF_PACKET, but I don't easily see why it couldn't be sent over the wire from adjacent network. Further Details: In the reproducer, the following network interface chain is set up: ┌────────────────┐ ┌────────────────┐ │ veth0_to_hsr ├───┤ hsr_slave0 ┼───┐ └────────────────┘ └────────────────┘ │ │ ┌──────┐ ├─┤ hsr0 ├───┐ │ └──────┘ │ ┌────────────────┐ ┌────────────────┐ │ │┌────────┐ │ veth1_to_hsr ┼───┤ hsr_slave1 ├───┘ └┤ │ └────────────────┘ └────────────────┘ ┌┼ bridge │ ││ │ │└────────┘ │ ┌───────┐ │ │ ... ├──────┘ └───────┘ To trigger the events leading up to crash, reproducer sends a corrupted HSR fr ---truncated---

Gravité et risque d'exploitation

CVE-2025-39703 obtient un score CVSS de 9.8/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.38 %, ce qui la place devant 30.0 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, 48b491a5cc74333c4a6a82fe21cea42c055a3b0b, <=6.12.*, 6.12.44, <b117c41b00902c1a7e24347c405cb82504aeae0b, <5.13, <=6.16.*, <61009439e4bd8d74e705ee15940760321be91d8a, 6.16.4, <3ae272ab523dd6bdc26e879027ed79feac9dd1b3, 0, 6.17, <acd69b597bd3f76d3b3d322b84082226c00eeaa4, 6.6.103, <7af76e9d18a9fd6f8611b3313c86c190f9b6a5a7, 5.12.9, <=5.10.*, <=6.6.*, 5.15.190, f6442ee08fe66c8e45c4f246531a2aaf4f17a7a7, 5.10.42, <5.10.241, 5.13, 6.1.149, 5.10.241, <=*, <=5.15.*, <8d9bc4a375a1ba05f7dfa0407de8e510ab9bd14d, <b640188b8a6690e685939053c7efdbc7818b5f4e, 4ffd1d4a6b306ff69cbe412d2c54d2dd349ff436) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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