{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-04-21T02:42:55.153","vulnerabilities":[{"cve":{"id":"CVE-2024-26804","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","published":"2024-04-04T09:15:09.217","lastModified":"2025-03-21T14:58:15.363","vulnStatus":"Analyzed","cveTags":[],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ip_tunnel: prevent perpetual headroom growth\n\nsyzkaller triggered following kasan splat:\nBUG: KASAN: use-after-free in __skb_flow_dissect+0x19d1/0x7a50 net/core/flow_dissector.c:1170\nRead of size 1 at addr ffff88812fb4000e by task syz-executor183/5191\n[..]\n kasan_report+0xda/0x110 mm/kasan/report.c:588\n __skb_flow_dissect+0x19d1/0x7a50 net/core/flow_dissector.c:1170\n skb_flow_dissect_flow_keys include/linux/skbuff.h:1514 [inline]\n ___skb_get_hash net/core/flow_dissector.c:1791 [inline]\n __skb_get_hash+0xc7/0x540 net/core/flow_dissector.c:1856\n skb_get_hash include/linux/skbuff.h:1556 [inline]\n ip_tunnel_xmit+0x1855/0x33c0 net/ipv4/ip_tunnel.c:748\n ipip_tunnel_xmit+0x3cc/0x4e0 net/ipv4/ipip.c:308\n __netdev_start_xmit include/linux/netdevice.h:4940 [inline]\n netdev_start_xmit include/linux/netdevice.h:4954 [inline]\n xmit_one net/core/dev.c:3548 [inline]\n dev_hard_start_xmit+0x13d/0x6d0 net/core/dev.c:3564\n __dev_queue_xmit+0x7c1/0x3d60 net/core/dev.c:4349\n dev_queue_xmit include/linux/netdevice.h:3134 [inline]\n neigh_connected_output+0x42c/0x5d0 net/core/neighbour.c:1592\n ...\n ip_finish_output2+0x833/0x2550 net/ipv4/ip_output.c:235\n ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:323\n ..\n iptunnel_xmit+0x5b4/0x9b0 net/ipv4/ip_tunnel_core.c:82\n ip_tunnel_xmit+0x1dbc/0x33c0 net/ipv4/ip_tunnel.c:831\n ipgre_xmit+0x4a1/0x980 net/ipv4/ip_gre.c:665\n __netdev_start_xmit include/linux/netdevice.h:4940 [inline]\n netdev_start_xmit include/linux/netdevice.h:4954 [inline]\n xmit_one net/core/dev.c:3548 [inline]\n dev_hard_start_xmit+0x13d/0x6d0 net/core/dev.c:3564\n ...\n\nThe splat occurs because skb->data points past skb->head allocated area.\nThis is because neigh layer does:\n  __skb_pull(skb, skb_network_offset(skb));\n\n... but skb_network_offset() returns a negative offset and __skb_pull()\narg is unsigned.  IOW, we skb->data gets \"adjusted\" by a huge value.\n\nThe negative value is returned because skb->head and skb->data distance is\nmore than 64k and skb->network_header (u16) has wrapped around.\n\nThe bug is in the ip_tunnel infrastructure, which can cause\ndev->needed_headroom to increment ad infinitum.\n\nThe syzkaller reproducer consists of packets getting routed via a gre\ntunnel, and route of gre encapsulated packets pointing at another (ipip)\ntunnel.  The ipip encapsulation finds gre0 as next output device.\n\nThis results in the following pattern:\n\n1). First packet is to be sent out via gre0.\nRoute lookup found an output device, ipip0.\n\n2).\nip_tunnel_xmit for gre0 bumps gre0->needed_headroom based on the future\noutput device, rt.dev->needed_headroom (ipip0).\n\n3).\nip output / start_xmit moves skb on to ipip0. which runs the same\ncode path again (xmit recursion).\n\n4).\nRouting step for the post-gre0-encap packet finds gre0 as output device\nto use for ipip0 encapsulated packet.\n\ntunl0->needed_headroom is then incremented based on the (already bumped)\ngre0 device headroom.\n\nThis repeats for every future packet:\n\ngre0->needed_headroom gets inflated because previous packets' ipip0 step\nincremented rt->dev (gre0) headroom, and ipip0 incremented because gre0\nneeded_headroom was increased.\n\nFor each subsequent packet, gre/ipip0->needed_headroom grows until\npost-expand-head reallocations result in a skb->head/data distance of\nmore than 64k.\n\nOnce that happens, skb->network_header (u16) wraps around when\npskb_expand_head tries to make sure that skb_network_offset() is unchanged\nafter the headroom expansion/reallocation.\n\nAfter this skb_network_offset(skb) returns a different (and negative)\nresult post headroom expansion.\n\nThe next trip to neigh layer (or anything else that would __skb_pull the\nnetwork header) makes skb->data point to a memory location outside\nskb->head area.\n\nv2: Cap the needed_headroom update to an arbitarily chosen upperlimit to\nprevent perpetual increase instead of dropping the headroom increment\ncompletely."},{"lang":"es","value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: ip_tunnel: evita el crecimiento perpetuo del espacio libre syzkaller activado después de kasan splat: ERROR: KASAN: use-after-free en __skb_flow_dissect+0x19d1/0x7a50 net/core/flow_dissector.c:1170 Lectura del tamaño 1 en la dirección ffff88812fb4000e mediante la tarea syz-executor183/5191 [..] kasan_report+0xda/0x110 mm/kasan/report.c:588 __skb_flow_dissect+0x19d1/0x7a50 net/core/flow_dissector.c:1170 skb_flow_dissect_flow_key incluir/linux /skbuff.h:1514 [en línea] ___skb_get_hash net/core/flow_dissector.c:1791 [en línea] __skb_get_hash+0xc7/0x540 net/core/flow_dissector.c:1856 skb_get_hash include/linux/skbuff.h:1556 [en línea] ip_tunnel_xmit +0x1855/0x33c0 net/ipv4/ip_tunnel.c:748 ipip_tunnel_xmit+0x3cc/0x4e0 net/ipv4/ipip.c:308 __netdev_start_xmit include/linux/netdevice.h:4940 [en línea] netdev_start_xmit include/linux/netdevice.h:4954 [en línea] xmit_one net/core/dev.c:3548 [en línea] dev_hard_start_xmit+0x13d/0x6d0 net/core/dev.c:3564 __dev_queue_xmit+0x7c1/0x3d60 net/core/dev.c:4349 dev_queue_xmit include/linux/netdevice .h:3134 [en línea] neigh_connected_output+0x42c/0x5d0 net/core/neighbour.c:1592 ... ip_finish_output2+0x833/0x2550 net/ipv4/ip_output.c:235 ip_finish_output+0x31/0x310 net/ipv4/ip_output.c :323 .. iptunnel_xmit+0x5b4/0x9b0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1dbc/0x33c0 net/ipv4/ip_tunnel.c:831 ipgre_xmit+0x4a1/0x980 net/ipv4/ip_gre.c:665 __netdev_start_xmit incluir /linux /netdevice.h:4940 [en línea] netdev_start_xmit include/linux/netdevice.h:4954 [en línea] xmit_one net/core/dev.c:3548 [en línea] dev_hard_start_xmit+0x13d/0x6d0 net/core/dev.c:3564 . .. El símbolo se produce porque skb->data apunta más allá del área asignada de skb->head. Esto se debe a que la capa vecina hace: __skb_pull(skb, skb_network_offset(skb)); ... pero skb_network_offset() devuelve un desplazamiento negativo y el argumento __skb_pull() no está firmado. OIA, nosotros, skb->los datos, se \"ajustan\" en un valor enorme. El valor negativo se devuelve porque la distancia de skb->head y skb->data es superior a 64k y skb->network_header (u16) se ha ajustado. El error está en la infraestructura ip_tunnel, lo que puede hacer que dev->needed_headroom se incremente hasta el infinito. El reproductor syzkaller consta de paquetes que se enrutan a través de un túnel gre y una ruta de paquetes encapsulados gre que apuntan a otro túnel (ipip). La encapsulación ipip encuentra gre0 como el siguiente dispositivo de salida. Esto da como resultado el siguiente patrón: 1). El primer paquete se enviará a través de gre0. La búsqueda de ruta encontró un dispositivo de salida, ipip0. 2). ip_tunnel_xmit para gre0 aumenta gre0->needed_headroom según el dispositivo de salida futuro, rt.dev->needed_headroom (ipip0). 3). ipoutput/start_xmit mueve skb a ipip0. que ejecuta la misma ruta de código nuevamente (xmit recursividad). 4). El paso de enrutamiento para el paquete post-gre0-encap encuentra gre0 como dispositivo de salida para usar con el paquete encapsulado ipip0. tunl0->needed_headroom luego se incrementa según el espacio libre del dispositivo gre0 (ya aumentado). Esto se repite para cada paquete futuro: gre0->needed_headroom se infla porque el paso ipip0 de los paquetes anteriores incrementó el espacio libre rt->dev (gre0), y ipip0 se incrementó porque se aumentó el espacio necesario_headroom de gre0. Para cada paquete posterior, gre/ipip0->needed_headroom crece hasta que las reasignaciones posteriores a la expansión del cabezal dan como resultado una distancia skb->head/data de más de 64k. Una vez que eso sucede, skb->network_header (u16) se ajusta cuando pskb_expand_head intenta asegurarse de que skb_network_offset() no cambie después de la expansión/reasignación del espacio libre. Después de esto, skb_network_offset(skb) devuelve un resultado diferente (y negativo) posterior a la expansión del espacio libre.---trucado---"}],"metrics":{"cvssMetricV31":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW"},"exploitabilityScore":3.9,"impactScore":1.4}]},"weaknesses":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","description":[{"lang":"en","value":"CWE-416"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"5.4.271","matchCriteriaId":"04A5E4E0-8C32-4FCD-9A72-B0AF07EA991E"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"5.10.212","matchCriteriaId":"01B34738-A022-44A9-9250-DCBC76539CB9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.15.151","matchCriteriaId":"EEAFD33E-C22F-4FB1-A417-9C96AB3E0358"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.1.81","matchCriteriaId":"EC825B0E-DFCA-4034-9B92-F111A4E2A732"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.21","matchCriteriaId":"B19074A2-9FE5-4E7D-9E2D-020F95013ADA"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.7.9","matchCriteriaId":"1C538467-EDA0-4A9A-82EB-2925DE9FF827"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.8:rc1:*:*:*:*:*:*","matchCriteriaId":"B9F4EA73-0894-400F-A490-3A397AB7A517"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.8:rc2:*:*:*:*:*:*","matchCriteriaId":"056BD938-0A27-4569-B391-30578B309EE3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.8:rc3:*:*:*:*:*:*","matchCriteriaId":"F02056A5-B362-4370-9FF8-6F0BD384D520"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.8:rc4:*:*:*:*:*:*","matchCriteriaId":"62075ACE-B2A0-4B16-829D-B3DA5AE5CC41"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.8:rc5:*:*:*:*:*:*","matchCriteriaId":"A780F817-2A77-4130-A9B7-5C25606314E3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.8:rc6:*:*:*:*:*:*","matchCriteriaId":"AEB9199B-AB8F-4877-8964-E2BA95B5F15C"}]}]},{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*","matchCriteriaId":"07B237A9-69A3-4A9C-9DA0-4E06BD37AE73"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/049d7989c67e8dd50f07a2096dbafdb41331fb9b","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/2e95350fe9db9d53c701075060ac8ac883b68aee","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/5ae1e9922bbdbaeb9cfbe91085ab75927488ac0f","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/a0a1db40b23e8ff86dea2786c5ea1470bb23ecb9","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/ab63de24ebea36fe73ac7121738595d704b66d96","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/afec0c5cd2ed71ca95a8b36a5e6d03333bf34282","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/f81e94d2dcd2397137edcb8b85f4c5bed5d22383","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/049d7989c67e8dd50f07a2096dbafdb41331fb9b","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/2e95350fe9db9d53c701075060ac8ac883b68aee","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/5ae1e9922bbdbaeb9cfbe91085ab75927488ac0f","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/a0a1db40b23e8ff86dea2786c5ea1470bb23ecb9","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/ab63de24ebea36fe73ac7121738595d704b66d96","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/afec0c5cd2ed71ca95a8b36a5e6d03333bf34282","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/f81e94d2dcd2397137edcb8b85f4c5bed5d22383","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"]},{"url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Mailing List","Third Party Advisory"]}]}}]}