CVE-2025-39673 (GCVE-0-2025-39673)
Vulnerability from cvelistv5
Published
2025-09-05 17:20
Modified
2025-09-29 05:57
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ppp: fix race conditions in ppp_fill_forward_path ppp_fill_forward_path() has two race conditions: 1. The ppp->channels list can change between list_empty() and list_first_entry(), as ppp_lock() is not held. If the only channel is deleted in ppp_disconnect_channel(), list_first_entry() may access an empty head or a freed entry, and trigger a panic. 2. pch->chan can be NULL. When ppp_unregister_channel() is called, pch->chan is set to NULL before pch is removed from ppp->channels. Fix these by using a lockless RCU approach: - Use list_first_or_null_rcu() to safely test and access the first list entry. - Convert list modifications on ppp->channels to their RCU variants and add synchronize_net() after removal. - Check for a NULL pch->chan before dereferencing it.
References
Impacted products
Vendor Product Version
Linux Linux Version: f6efc675c9dd8d93f826b79ae7e33e03301db609
Version: f6efc675c9dd8d93f826b79ae7e33e03301db609
Version: f6efc675c9dd8d93f826b79ae7e33e03301db609
Version: f6efc675c9dd8d93f826b79ae7e33e03301db609
Version: f6efc675c9dd8d93f826b79ae7e33e03301db609
Version: f6efc675c9dd8d93f826b79ae7e33e03301db609
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ppp/ppp_generic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7",
              "status": "affected",
              "version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
              "versionType": "git"
            },
            {
              "lessThan": "0f1630be6fcca3f0c63e4b242ad202e5cde28a40",
              "status": "affected",
              "version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
              "versionType": "git"
            },
            {
              "lessThan": "ca18d751bcc9faf5b7e82e9fae1223d103928181",
              "status": "affected",
              "version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
              "versionType": "git"
            },
            {
              "lessThan": "94731cc551e29511d85aa8dec61a6c071b1f2430",
              "status": "affected",
              "version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
              "versionType": "git"
            },
            {
              "lessThan": "f97f6475fdcb3c28ff3c55cc4b7bde632119ec08",
              "status": "affected",
              "version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
              "versionType": "git"
            },
            {
              "lessThan": "0417adf367a0af11adf7ace849af4638cfb573f7",
              "status": "affected",
              "version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ppp/ppp_generic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.13"
            },
            {
              "lessThan": "5.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.190",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.149",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.103",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.44",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.190",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.149",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.103",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.44",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16.4",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nppp: fix race conditions in ppp_fill_forward_path\n\nppp_fill_forward_path() has two race conditions:\n\n1. The ppp-\u003echannels list can change between list_empty() and\n   list_first_entry(), as ppp_lock() is not held. If the only channel\n   is deleted in ppp_disconnect_channel(), list_first_entry() may\n   access an empty head or a freed entry, and trigger a panic.\n\n2. pch-\u003echan can be NULL. When ppp_unregister_channel() is called,\n   pch-\u003echan is set to NULL before pch is removed from ppp-\u003echannels.\n\nFix these by using a lockless RCU approach:\n- Use list_first_or_null_rcu() to safely test and access the first list\n  entry.\n- Convert list modifications on ppp-\u003echannels to their RCU variants and\n  add synchronize_net() after removal.\n- Check for a NULL pch-\u003echan before dereferencing it."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-09-29T05:57:08.160Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7"
        },
        {
          "url": "https://git.kernel.org/stable/c/0f1630be6fcca3f0c63e4b242ad202e5cde28a40"
        },
        {
          "url": "https://git.kernel.org/stable/c/ca18d751bcc9faf5b7e82e9fae1223d103928181"
        },
        {
          "url": "https://git.kernel.org/stable/c/94731cc551e29511d85aa8dec61a6c071b1f2430"
        },
        {
          "url": "https://git.kernel.org/stable/c/f97f6475fdcb3c28ff3c55cc4b7bde632119ec08"
        },
        {
          "url": "https://git.kernel.org/stable/c/0417adf367a0af11adf7ace849af4638cfb573f7"
        }
      ],
      "title": "ppp: fix race conditions in ppp_fill_forward_path",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-39673",
    "datePublished": "2025-09-05T17:20:38.769Z",
    "dateReserved": "2025-04-16T07:20:57.112Z",
    "dateUpdated": "2025-09-29T05:57:08.160Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-39673\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-09-05T18:15:43.230\",\"lastModified\":\"2025-09-08T16:25:38.810\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nppp: fix race conditions in ppp_fill_forward_path\\n\\nppp_fill_forward_path() has two race conditions:\\n\\n1. The ppp-\u003echannels list can change between list_empty() and\\n   list_first_entry(), as ppp_lock() is not held. If the only channel\\n   is deleted in ppp_disconnect_channel(), list_first_entry() may\\n   access an empty head or a freed entry, and trigger a panic.\\n\\n2. pch-\u003echan can be NULL. When ppp_unregister_channel() is called,\\n   pch-\u003echan is set to NULL before pch is removed from ppp-\u003echannels.\\n\\nFix these by using a lockless RCU approach:\\n- Use list_first_or_null_rcu() to safely test and access the first list\\n  entry.\\n- Convert list modifications on ppp-\u003echannels to their RCU variants and\\n  add synchronize_net() after removal.\\n- Check for a NULL pch-\u003echan before dereferencing it.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0417adf367a0af11adf7ace849af4638cfb573f7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/0f1630be6fcca3f0c63e4b242ad202e5cde28a40\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/94731cc551e29511d85aa8dec61a6c071b1f2430\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ca18d751bcc9faf5b7e82e9fae1223d103928181\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f97f6475fdcb3c28ff3c55cc4b7bde632119ec08\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.