CVE-2025-38638 (GCVE-0-2025-38638)
Vulnerability from cvelistv5
Published
2025-08-22 16:00
Modified
2025-08-22 16:00
Severity ?
Summary
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: 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
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0bdca3439a22c70eb8f404acd61bf7aca5d731b0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ea2f921db7a483a526058c5b5b8162edd88dabe5
Impacted products
Vendor Product Version
Linux Linux Version: 169fd62799e8acabbfb4760799be11138ced949c
Version: 169fd62799e8acabbfb4760799be11138ced949c
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   Linux Linux Version: 6.16
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/route.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0bdca3439a22c70eb8f404acd61bf7aca5d731b0",
              "status": "affected",
              "version": "169fd62799e8acabbfb4760799be11138ced949c",
              "versionType": "git"
            },
            {
              "lessThan": "ea2f921db7a483a526058c5b5b8162edd88dabe5",
              "status": "affected",
              "version": "169fd62799e8acabbfb4760799be11138ced949c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/route.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16.1",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17-rc1",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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 \u003c0f\u003e 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 \u003cTASK\u003e\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"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-08-22T16:00:44.913Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0bdca3439a22c70eb8f404acd61bf7aca5d731b0"
        },
        {
          "url": "https://git.kernel.org/stable/c/ea2f921db7a483a526058c5b5b8162edd88dabe5"
        }
      ],
      "title": "ipv6: add a retry logic in net6_rt_notify()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-38638",
    "datePublished": "2025-08-22T16:00:44.913Z",
    "dateReserved": "2025-04-16T04:51:24.030Z",
    "dateUpdated": "2025-08-22T16:00:44.913Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-38638\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-08-22T16:15:37.713\",\"lastModified\":\"2025-08-22T18:08:51.663\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"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 \u003c0f\u003e 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 \u003cTASK\u003e\\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\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0bdca3439a22c70eb8f404acd61bf7aca5d731b0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ea2f921db7a483a526058c5b5b8162edd88dabe5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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