{"id":"CVE-2024-49949","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: avoid potential underflow in qdisc_pkt_len_init() with UFO\n\nAfter commit 7c6d2ecbda83 (\"net: be more gentle about silly gso\nrequests coming from user\") virtio_net_…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: avoid potential underflow in qdisc_pkt_len_init() with UFO\n\nAfter commit 7c6d2ecbda83 (\"net: be more gentle about silly gso\nrequests coming from user\") virtio_net_…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-476"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 4.14.256, < 4.19","linux_kernel >= 4.19.218, < 5.4","linux_kernel >= 5.4.162, < 5.10","linux_kernel >= 5.10.82, < 5.10.227","linux_kernel >= 5.15.5, < 5.15.168","linux_kernel >= 5.16, < 6.1.113","linux_kernel >= 6.2, < 6.6.55","linux_kernel >= 6.7, < 6.10.14","linux_kernel >= 6.11, < 6.11.3","linux_kernel = 6.12"],"patched":["linux_kernel 6.11.3"],"published":"2024-10-21","updated":"2026-10-15","sourceUpdated":"2026-10-15T01:19:01.900","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2024-49949","references":[{"url":"https://git.kernel.org/stable/c/1598d70ad9c7d0a4d9d54b82094e9f45908fda6d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/25ab0b87dbd89cecef8a9c60a02bb97832e471d1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/81fd007dcd47c34471766249853e4d4bce8eea4b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/939c88cbdc668dadd8cfa7a35d9066331239041c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ba26060a29d3ca1bfc737aa79f7125128f35147c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c20029db28399ecc50e556964eaba75c43b1e2f1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d6114993e0a89fde84a60a60a8329a571580b174","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d70ca7598943572d5e384227bd268acb5109bf72","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f959cce8a2a04ce776aa8b78e83ce339e0d7fbac","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-265688.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-355557.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-398330.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.0028,"epssPercentile":0.20321,"ingestedAt":"2026-10-15T03:30:12.755Z","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2024-10-22T13:36:39.259120Z"},"slug":"CVE-2024-49949","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: avoid potential underflow in qdisc_pkt_len_init() with UFO\n\nAfter commit 7c6d2ecbda83 (\"net: be more gentle about silly gso\nrequests coming from user\") virtio_net_hdr_to_skb() had sanity check\nto detect malicious attempts from user space to cook a bad GSO packet.\n\nThen commit cf9acc90c80ec (\"net: virtio_net_hdr_to_skb: count\ntransport header in UFO\") while fixing one issue, allowed user space\nto cook a GSO packet with the following characteristic :\n\nIPv4 SKB_GSO_UDP, gso_size=3, skb->len = 28.\n\nWhen this packet arrives in qdisc_pkt_len_init(), we end up\nwith hdr_len = 28 (IPv4 header + UDP header), matching skb->len\n\nThen the following sets gso_segs to 0 :\n\ngso_segs = DIV_ROUND_UP(skb->len - hdr_len,\n                        shinfo->gso_size);\n\nThen later we set qdisc_skb_cb(skb)->pkt_len to back to zero :/\n\nqdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len;\n\nThis leads to the following crash in fq_codel [1]\n\nqdisc_pkt_len_init() is best effort, we only want an estimation\nof the bytes sent on the wire, not crashing the kernel.\n\nThis patch is fixing this particular issue, a following one\nadds more sanity checks for another potential bug.\n\n[1]\n[   70.724101] BUG: kernel NULL pointer dereference, address: 0000000000000000\n[   70.724561] #PF: supervisor read access in kernel mode\n[   70.724561] #PF: error_code(0x0000) - not-present page\n[   70.724561] PGD 10ac61067 P4D 10ac61067 PUD 107ee2067 PMD 0\n[   70.724561] Oops: Oops: 0000 [#1] SMP NOPTI\n[   70.724561] CPU: 11 UID: 0 PID: 2163 Comm: b358537762 Not tainted 6.11.0-virtme #991\n[   70.724561] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[   70.724561] RIP: 0010:fq_codel_enqueue (net/sched/sch_fq_codel.c:120 net/sched/sch_fq_codel.c:168 net/sched/sch_fq_codel.c:230) sch_fq_codel\n[ 70.724561] Code: 24 08 49 c1 e1 06 44 89 7c 24 18 45 31 ed 45 31 c0 31 ff 89 44 24 14 4c 03 8b 90 01 00 00 eb 04 39 ca 73 37 4d 8b 39 83 c7 01 <49> 8b 17 49 89 11 41 8b 57 28 45 8b 5f 34 49 c7 07 00 00 00 00 49\nAll code\n========\n   0:\t24 08                \tand    $0x8,%al\n   2:\t49 c1 e1 06          \tshl    $0x6,%r9\n   6:\t44 89 7c 24 18       \tmov    %r15d,0x18(%rsp)\n   b:\t45 31 ed             \txor    %r13d,%r13d\n   e:\t45 31 c0             \txor    %r8d,%r8d\n  11:\t31 ff                \txor    %edi,%edi\n  13:\t89 44 24 14          \tmov    %eax,0x14(%rsp)\n  17:\t4c 03 8b 90 01 00 00 \tadd    0x190(%rbx),%r9\n  1e:\teb 04                \tjmp    0x24\n  20:\t39 ca                \tcmp    %ecx,%edx\n  22:\t73 37                \tjae    0x5b\n  24:\t4d 8b 39             \tmov    (%r9),%r15\n  27:\t83 c7 01             \tadd    $0x1,%edi\n  2a:*\t49 8b 17             \tmov    (%r15),%rdx\t\t<-- trapping instruction\n  2d:\t49 89 11             \tmov    %rdx,(%r9)\n  30:\t41 8b 57 28          \tmov    0x28(%r15),%edx\n  34:\t45 8b 5f 34          \tmov    0x34(%r15),%r11d\n  38:\t49 c7 07 00 00 00 00 \tmovq   $0x0,(%r15)\n  3f:\t49                   \trex.WB\n\nCode starting with the faulting instruction\n===========================================\n   0:\t49 8b 17             \tmov    (%r15),%rdx\n   3:\t49 89 11             \tmov    %rdx,(%r9)\n   6:\t41 8b 57 28          \tmov    0x28(%r15),%edx\n   a:\t45 8b 5f 34          \tmov    0x34(%r15),%r11d\n   e:\t49 c7 07 00 00 00 00 \tmovq   $0x0,(%r15)\n  15:\t49                   \trex.WB\n[   70.724561] RSP: 0018:ffff95ae85e6fb90 EFLAGS: 00000202\n[   70.724561] RAX: 0000000002000000 RBX: ffff95ae841de000 RCX: 0000000000000000\n[   70.724561] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001\n[   70.724561] RBP: ffff95ae85e6fbf8 R08: 0000000000000000 R09: ffff95b710a30000\n[   70.724561] R10: 0000000000000000 R11: bdf289445ce31881 R12: ffff95ae85e6fc58\n[   70.724561] R13: 0000000000000000 R14: 0000000000000040 R15: 0000000000000000\n[   70.724561] FS:  000000002c5c1380(0000) GS:ffff95bd7fcc0000(0000) knlGS:0000000000000000\n[   70.724561] CS:  0010 DS: 0000 ES: 0000 C\n---truncated---\n\n## Affected\n\n- `linux_kernel >= 4.14.256, < 4.19`\n- `linux_kernel >= 4.19.218, < 5.4`\n- `linux_kernel >= 5.4.162, < 5.10`\n- `linux_kernel >= 5.10.82, < 5.10.227`\n- `linux_kernel >= 5.15.5, < 5.15.168`\n- `linux_kernel >= 5.16, < 6.1.113`\n- `linux_kernel >= 6.2, < 6.6.55`\n- `linux_kernel >= 6.7, < 6.10.14`\n- `linux_kernel >= 6.11, < 6.11.3`\n- `linux_kernel = 6.12`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.11.3`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}