FKIE_CVE-2026-53240

Vulnerability from fkie_nvd - Published: 2026-06-25 09:16 - Updated: 2026-06-30 14:44
Severity
8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload __input_process_payload() stores first_skb into xtfs->ra_newskb under drop_lock when starting partial reassembly, then unlocks and breaks out of the processing loop. The post-loop check reads xtfs->ra_newskb without the lock to decide whether first_skb is still owned: if (first_skb && first_iplen && !defer && first_skb != xtfs->ra_newskb) Between spin_unlock and this read, a concurrent CPU running iptfs_reassem_cont() (or the drop_timer hrtimer) can complete reassembly, NULL xtfs->ra_newskb, and free the skb. The check then evaluates first_skb != NULL as true, and pskb_trim/ip_summed/consume_skb operate on the freed skb — a use-after-free in skbuff_head_cache. Replace the unlocked read with a local bool that records whether first_skb was handed to the reassembly state in the current call. The flag is set after the existing spin_unlock, before the break, using the pointer equality that is stable at that point (first_skb == skb iff first_skb was stored in ra_newskb).
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8d9a79fbf5172d9c4c0146057af2360913265a11
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/eb48730bb827d1550401a5d391903f9d90b493c8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ff2ee35b6ce5fa8a8e24ea50b15733d5c8780198
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/xfrm/xfrm_iptfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8d9a79fbf5172d9c4c0146057af2360913265a11",
              "status": "affected",
              "version": "3f3339885fb343b7b42d7c34717108ce07da24ae",
              "versionType": "git"
            },
            {
              "lessThan": "ff2ee35b6ce5fa8a8e24ea50b15733d5c8780198",
              "status": "affected",
              "version": "3f3339885fb343b7b42d7c34717108ce07da24ae",
              "versionType": "git"
            },
            {
              "lessThan": "eb48730bb827d1550401a5d391903f9d90b493c8",
              "status": "affected",
              "version": "3f3339885fb343b7b42d7c34717108ce07da24ae",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/xfrm/xfrm_iptfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.36",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: fix use-after-free on first_skb in __input_process_payload\n\n__input_process_payload() stores first_skb into xtfs-\u003era_newskb under\ndrop_lock when starting partial reassembly, then unlocks and breaks out\nof the processing loop. The post-loop check reads xtfs-\u003era_newskb\nwithout the lock to decide whether first_skb is still owned:\n\n    if (first_skb \u0026\u0026 first_iplen \u0026\u0026 !defer \u0026\u0026 first_skb != xtfs-\u003era_newskb)\n\nBetween spin_unlock and this read, a concurrent CPU running\niptfs_reassem_cont() (or the drop_timer hrtimer) can complete\nreassembly, NULL xtfs-\u003era_newskb, and free the skb. The check then\nevaluates first_skb != NULL as true, and pskb_trim/ip_summed/consume_skb\noperate on the freed skb \u2014 a use-after-free in skbuff_head_cache.\n\nReplace the unlocked read with a local bool that records whether\nfirst_skb was handed to the reassembly state in the current call. The\nflag is set after the existing spin_unlock, before the break, using the\npointer equality that is stable at that point (first_skb == skb iff\nfirst_skb was stored in ra_newskb)."
    }
  ],
  "id": "CVE-2026-53240",
  "lastModified": "2026-06-30T14:44:27.313",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-06-25T09:16:41.960",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8d9a79fbf5172d9c4c0146057af2360913265a11"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/eb48730bb827d1550401a5d391903f9d90b493c8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ff2ee35b6ce5fa8a8e24ea50b15733d5c8780198"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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