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CVE-2026-53240 (GCVE-0-2026-53240)

Vulnerability from cvelistv5 – Published: 2026-06-25 08:39 – Updated: 2026-08-05 12:34
VLAI
Title
xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload
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).
Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 3f3339885fb343b7b42d7c34717108ce07da24ae , < 8d9a79fbf5172d9c4c0146057af2360913265a11 (git)
Affected: 3f3339885fb343b7b42d7c34717108ce07da24ae , < ff2ee35b6ce5fa8a8e24ea50b15733d5c8780198 (git)
Affected: 3f3339885fb343b7b42d7c34717108ce07da24ae , < eb48730bb827d1550401a5d391903f9d90b493c8 (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.18.36 , ≤ 6.18.* (semver)
Unaffected: 7.0.13 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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      "cve": "CVE-2026-53240",
      "id": "CVE-2026-53240",
      "initial_release_date": "2026-06-25T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53240.json",
      "version": "3"
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      "current_release_date": "2026-08-06T01:13:51Z",
      "cve": "CVE-2026-53240",
      "id": "CVE-2026-53240",
      "initial_release_date": "2026-06-26T02:09:00Z",
      "product_status:known_not_affected": "293",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-53240",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-53240.json",
      "version": "6"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


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