CVE-2025-38638

Estado: AnalizadaMedia (5.5)—

In the Linux kernel, the following vulnerability has been resolved:

ipv6: add a retry logic in net6_rt_notify()

inet6_rt_notify() can be called under RCU protection only. This means the route could be changed concurrently and rt6_fill_node() could return -EMSGSIZE.

Re-size the skb when this happens and retry, removing one WARN_ON() that syzbot was able to trigger:

Detalles técnicos trazas, registros y código del informe original

WARNING: CPU: 3 PID: 6291 at net/ipv6/route.c:6342 inet6_rt_notify+0x475/0x4b0 net/ipv6/route.c:6342
Modules linked in:
CPU: 3 UID: 0 PID: 6291 Comm: syz.0.77 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
 RIP: 0010:inet6_rt_notify+0x475/0x4b0 net/ipv6/route.c:6342
Code: fc ff ff e8 6d 52 ea f7 e9 47 fc ff ff 48 8b 7c 24 08 4c 89 04 24 e8 5a 52 ea f7 4c 8b 04 24 e9 94 fd ff ff e8 9c fe 84 f7 90 <0f> 0b 90 e9 bd fd ff ff e8 6e 52 ea f7 e9 bb fb ff ff 48 89 df e8
RSP: 0018:ffffc900035cf1d8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffc900035cf540 RCX: ffffffff8a36e790
RDX: ffff88802f7e8000 RSI: ffffffff8a36e9d4 RDI: 0000000000000005
RBP: ffff88803c230f00 R08: 0000000000000005 R09: 00000000ffffffa6
R10: 00000000ffffffa6 R11: 0000000000000001 R12: 00000000ffffffa6
R13: 0000000000000900 R14: ffff888032ea4100 R15: 0000000000000000
FS:  00007fac7b89a6c0(0000) GS:ffff8880d6a20000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fac7b899f98 CR3: 0000000034b3f000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
  ip6_route_mpath_notify+0xde/0x280 net/ipv6/route.c:5356
  ip6_route_multipath_add+0x1181/0x1bd0 net/ipv6/route.c:5536
  inet6_rtm_newroute+0xe4/0x1a0 net/ipv6/route.c:5647
  rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6944
  netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2552
  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
  netlink_unicast+0x58d/0x850 net/netlink/af_netlink.c:1346
  netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896
  sock_sendmsg_nosec net/socket.c:712 [inline]
  __sock_sendmsg net/socket.c:727 [inline]
  ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566
  ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 5.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.14%
Percentil entre todas las CVEs puntuadas: 3
Fecha de la puntuación: 5/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

NVD-CWE-noinfo

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2025-38638",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "169fd62799e8acabbfb4760799be11138ced949c",
              "lessThan": "0bdca3439a22c70eb8f404acd61bf7aca5d731b0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "169fd62799e8acabbfb4760799be11138ced949c",
              "lessThan": "ea2f921db7a483a526058c5b5b8162edd88dabe5",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/ipv6/route.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.16",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.16.1",
              "versionType": "semver",
              "lessThanOrEqual": "6.16.*"
            },
            {
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/ipv6/route.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-08-22T16:15:37.713",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0bdca3439a22c70eb8f404acd61bf7aca5d731b0",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ea2f921db7a483a526058c5b5b8162edd88dabe5",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: add a retry logic in net6_rt_notify()\n\ninet6_rt_notify() can be called under RCU protection only.\nThis means the route could be changed concurrently\nand rt6_fill_node() could return -EMSGSIZE.\n\nRe-size the skb when this happens and retry, removing\none WARN_ON() that syzbot was able to trigger:\n\nWARNING: CPU: 3 PID: 6291 at net/ipv6/route.c:6342 inet6_rt_notify+0x475/0x4b0 net/ipv6/route.c:6342\nModules linked in:\nCPU: 3 UID: 0 PID: 6291 Comm: syz.0.77 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full)\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\n RIP: 0010:inet6_rt_notify+0x475/0x4b0 net/ipv6/route.c:6342\nCode: fc ff ff e8 6d 52 ea f7 e9 47 fc ff ff 48 8b 7c 24 08 4c 89 04 24 e8 5a 52 ea f7 4c 8b 04 24 e9 94 fd ff ff e8 9c fe 84 f7 90 <0f> 0b 90 e9 bd fd ff ff e8 6e 52 ea f7 e9 bb fb ff ff 48 89 df e8\nRSP: 0018:ffffc900035cf1d8 EFLAGS: 00010293\nRAX: 0000000000000000 RBX: ffffc900035cf540 RCX: ffffffff8a36e790\nRDX: ffff88802f7e8000 RSI: ffffffff8a36e9d4 RDI: 0000000000000005\nRBP: ffff88803c230f00 R08: 0000000000000005 R09: 00000000ffffffa6\nR10: 00000000ffffffa6 R11: 0000000000000001 R12: 00000000ffffffa6\nR13: 0000000000000900 R14: ffff888032ea4100 R15: 0000000000000000\nFS:  00007fac7b89a6c0(0000) GS:ffff8880d6a20000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007fac7b899f98 CR3: 0000000034b3f000 CR4: 0000000000352ef0\nCall Trace:\n <TASK>\n  ip6_route_mpath_notify+0xde/0x280 net/ipv6/route.c:5356\n  ip6_route_multipath_add+0x1181/0x1bd0 net/ipv6/route.c:5536\n  inet6_rtm_newroute+0xe4/0x1a0 net/ipv6/route.c:5647\n  rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6944\n  netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2552\n  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]\n  netlink_unicast+0x58d/0x850 net/netlink/af_netlink.c:1346\n  netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896\n  sock_sendmsg_nosec net/socket.c:712 [inline]\n  __sock_sendmsg net/socket.c:727 [inline]\n  ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566\n  ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ipv6: añadir una lógica de reintento en net6_rt_notify(). inet6_rt_notify() solo se puede ejecutar bajo la protección de RCU. Esto significa que la ruta podría modificarse simultáneamente y que rt6_fill_node() podría devolver -EMSGSIZE. Redimensione el skb cuando esto suceda y vuelva a intentarlo, eliminando un WARN_ON() que syzbot pudo activar: WARNING: CPU: 3 PID: 6291 at net/ipv6/route.c:6342 inet6_rt_notify+0x475/0x4b0 net/ipv6/route.c:6342 Modules linked in: CPU: 3 UID: 0 PID: 6291 Comm: syz.0.77 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:inet6_rt_notify+0x475/0x4b0 net/ipv6/route.c:6342 Code: fc ff ff e8 6d 52 ea f7 e9 47 fc ff ff 48 8b 7c 24 08 4c 89 04 24 e8 5a 52 ea f7 4c 8b 04 24 e9 94 fd ff ff e8 9c fe 84 f7 90 &lt;0f&gt; 0b 90 e9 bd fd ff ff e8 6e 52 ea f7 e9 bb fb ff ff 48 89 df e8 RSP: 0018:ffffc900035cf1d8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffffc900035cf540 RCX: ffffffff8a36e790 RDX: ffff88802f7e8000 RSI: ffffffff8a36e9d4 RDI: 0000000000000005 RBP: ffff88803c230f00 R08: 0000000000000005 R09: 00000000ffffffa6 R10: 00000000ffffffa6 R11: 0000000000000001 R12: 00000000ffffffa6 R13: 0000000000000900 R14: ffff888032ea4100 R15: 0000000000000000 FS: 00007fac7b89a6c0(0000) GS:ffff8880d6a20000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fac7b899f98 CR3: 0000000034b3f000 CR4: 0000000000352ef0 Call Trace:  ip6_route_mpath_notify+0xde/0x280 net/ipv6/route.c:5356 ip6_route_multipath_add+0x1181/0x1bd0 net/ipv6/route.c:5536 inet6_rtm_newroute+0xe4/0x1a0 net/ipv6/route.c:5647 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6944 netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x58d/0x850 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620"
    }
  ],
  "lastModified": "2026-06-17T09:17:16.070",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.16:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "D6BFC4F7-7099-4420-AF39-DD1CEABB8DF9"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}