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CVE-2026-80839 (GCVE-0-2026-80839)

Vulnerability from cvelistv5 – Published: 2026-09-04 15:54 – Updated: 2026-09-04 15:54
VLAI
Title
batman-adv: reject unrepresentable multicast TVLV offsets
Summary
In the Linux kernel, the following vulnerability has been resolved: batman-adv: reject unrepresentable multicast TVLV offsets The network and transport header fields in struct sk_buff are 16-bit offsets from skb->head, and U16_MAX is reserved as the unset transport header value. batadv_tvlv_call_handler() sets both fields from a received multicast TVLV without checking whether the TVLV end is representable. If the end offset exceeds the field's range, skb_set_transport_header() truncates it so that the transport header precedes the network header. The negative difference is then returned by skb_network_header_len() as a large u32. batadv_mcast_forw_packet() consequently accepts an oversized multicast tracker and accesses memory beyond the skb data. Add skb_set_transport_header_careful(), an offset-aware counterpart to skb_reset_transport_header_careful(), which validates the final head-relative offset before assigning it. Use the new helper in batadv_tvlv_call_handler() and reject unrepresentable TVLVs before setting the network header.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 07afe1ba288c04280622fa002ed385f1ac0b6fe6 , < da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2 (git)
Affected: 07afe1ba288c04280622fa002ed385f1ac0b6fe6 , < 916ec741e65af072b98e475feaad98c063da1b7c (git)
Affected: 07afe1ba288c04280622fa002ed385f1ac0b6fe6 , < 1b466746fe109127fd983100a228cdd1f1f6ece2 (git)
Affected: 07afe1ba288c04280622fa002ed385f1ac0b6fe6 , < 2b46baa591d0a7c16b62f150917187e70d053be6 (git)
Affected: 07afe1ba288c04280622fa002ed385f1ac0b6fe6 , < f12c2de4f542e3220e17e0606f492110064f04cb (git)
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Linux Linux Affected: 6.8
Unaffected: 0 , < 6.8 (semver)
Unaffected: 6.12.108 , ≤ 6.12.* (semver)
Unaffected: 6.18.49 , ≤ 6.18.* (semver)
Unaffected: 7.1.13 , ≤ 7.1.* (semver)
Unaffected: 7.2.3 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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Show details on NVD website
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{
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      "affected": [
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          "product": "Linux",
          "programFiles": [
            "include/linux/skbuff.h",
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: reject unrepresentable multicast TVLV offsets\n\nThe network and transport header fields in struct sk_buff are 16-bit\noffsets from skb-\u003ehead, and U16_MAX is reserved as the unset transport\nheader value. batadv_tvlv_call_handler() sets both fields from a received\nmulticast TVLV without checking whether the TVLV end is representable.\n\nIf the end offset exceeds the field\u0027s range, skb_set_transport_header()\ntruncates it so that the transport header precedes the network header.\nThe negative difference is then returned by skb_network_header_len() as\na large u32. batadv_mcast_forw_packet() consequently accepts an oversized\nmulticast tracker and accesses memory beyond the skb data.\n\nAdd skb_set_transport_header_careful(), an offset-aware counterpart to\nskb_reset_transport_header_careful(), which validates the final\nhead-relative offset before assigning it. Use the new helper in\nbatadv_tvlv_call_handler() and reject unrepresentable TVLVs before\nsetting the network header."
        }
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    "dateReserved": "2026-08-26T14:34:25.796Z",
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: reject unrepresentable multicast TVLV offsets\n\nThe network and transport header fields in struct sk_buff are 16-bit\noffsets from skb-\u003ehead, and U16_MAX is reserved as the unset transport\nheader value. batadv_tvlv_call_handler() sets both fields from a received\nmulticast TVLV without checking whether the TVLV end is representable.\n\nIf the end offset exceeds the field\u0027s range, skb_set_transport_header()\ntruncates it so that the transport header precedes the network header.\nThe negative difference is then returned by skb_network_header_len() as\na large u32. batadv_mcast_forw_packet() consequently accepts an oversized\nmulticast tracker and accesses memory beyond the skb data.\n\nAdd skb_set_transport_header_careful(), an offset-aware counterpart to\nskb_reset_transport_header_careful(), which validates the final\nhead-relative offset before assigning it. Use the new helper in\nbatadv_tvlv_call_handler() and reject unrepresentable TVLVs before\nsetting the network header."
          }
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      "current_release_date": "2026-09-10T01:50:51Z",
      "cve": "CVE-2026-80839",
      "id": "CVE-2026-80839",
      "initial_release_date": "2026-09-05T00:26:25Z",
      "product_status:known_not_affected": "353",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-80839",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-80839.json",
      "version": "4"
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  }
}



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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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.