CVE-2026-80742 (GCVE-0-2026-80742)

Vulnerability from cvelistv5 – Published: 2026-09-03 08:26 – Updated: 2026-09-03 08:26
VLAI
Title
af_packet: Don't send zero-byte data in tpacket_snd().
Summary
In the Linux kernel, the following vulnerability has been resolved: af_packet: Don't send zero-byte data in tpacket_snd(). syzbot reported a WARNING in __dev_queue_xmit() triggered via tpacket_snd(): skb_assert_len WARNING: at include/linux/skbuff.h:2753 skb_assert_len WARNING: at __dev_queue_xmit+0x21bc/0x4970 net/core/dev.c:4781 Call Trace: <TASK> dev_queue_xmit include/linux/netdevice.h:3448 [inline] packet_xmit+0x243/0x310 net/packet/af_packet.c:276 tpacket_snd net/packet/af_packet.c:2907 [inline] packet_sendmsg+0x28d6/0x4eb0 net/packet/af_packet.c:3134 When sending 0-byte packets via TPACKET ring buffer on devices with no hard header (e.g. dev->hard_header_len == 0), tpacket_fill_skb() populates an skb with skb->len == 0 and returns 0. tpacket_snd() then forwards this empty skb to packet_xmit(), causing __dev_queue_xmit() to hit skb_assert_len(skb). Similar checks exist in packet_snd() via commit dc633700f00f ("net/af_packet: check len when min_header_len equals to 0") and in packet_sendmsg_spkt() via commit 6a341729fb31 ("af_packet: Don't send zero-byte data in packet_sendmsg_spkt()."). Return -EINVAL in tpacket_fill_skb() when skb->len is zero to reject zero-length packets in tpacket_snd().
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < dde212f8622f5cb36223fff1ebd6e6f2a3dc61fe (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 80a702964467b998d254f16cc61c2c9a20540c9d (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 7521e691c7c4f2231634c95053281ac888d1f452 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 1fc70b3d513bafb16b17540178870ef46e81c0bb (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 3fa110f9e2ea96f567f2194c673c4bc327640111 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 98c5914d6b7bd4b4675535908e57dea31f1efd6a (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < f09ac5682f1bb67981fcb6ead4d3cfe439225876 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 6bcd76c134c55c697148acb5c0194e9666abdf84 (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.12
Unaffected: 0 , < 2.6.12 (semver)
Unaffected: 5.10.266 , ≤ 5.10.* (semver)
Unaffected: 5.15.217 , ≤ 5.15.* (semver)
Unaffected: 6.1.184 , ≤ 6.1.* (semver)
Unaffected: 6.6.153 , ≤ 6.6.* (semver)
Unaffected: 6.12.105 , ≤ 6.12.* (semver)
Unaffected: 6.18.46 , ≤ 6.18.* (semver)
Unaffected: 7.1.10 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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{
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\naf_packet: Don\u0027t send zero-byte data in tpacket_snd().\n\nsyzbot reported a WARNING in __dev_queue_xmit() triggered via tpacket_snd():\n\nskb_assert_len\nWARNING: at include/linux/skbuff.h:2753 skb_assert_len\nWARNING: at __dev_queue_xmit+0x21bc/0x4970 net/core/dev.c:4781\n\nCall Trace:\n \u003cTASK\u003e\n dev_queue_xmit include/linux/netdevice.h:3448 [inline]\n packet_xmit+0x243/0x310 net/packet/af_packet.c:276\n tpacket_snd net/packet/af_packet.c:2907 [inline]\n packet_sendmsg+0x28d6/0x4eb0 net/packet/af_packet.c:3134\n\nWhen sending 0-byte packets via TPACKET ring buffer on devices with no\nhard header (e.g. dev-\u003ehard_header_len == 0), tpacket_fill_skb()\npopulates an skb with skb-\u003elen == 0 and returns 0. tpacket_snd() then\nforwards this empty skb to packet_xmit(), causing __dev_queue_xmit() to\nhit skb_assert_len(skb).\n\nSimilar checks exist in packet_snd() via commit dc633700f00f\n(\"net/af_packet: check len when min_header_len equals to 0\") and in\npacket_sendmsg_spkt() via commit 6a341729fb31 (\"af_packet: Don\u0027t send\nzero-byte data in packet_sendmsg_spkt().\").\n\nReturn -EINVAL in tpacket_fill_skb() when skb-\u003elen is zero to reject\nzero-length packets in tpacket_snd()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-03T08:26:25.920Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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        },
        {
          "url": "https://git.kernel.org/stable/c/80a702964467b998d254f16cc61c2c9a20540c9d"
        },
        {
          "url": "https://git.kernel.org/stable/c/7521e691c7c4f2231634c95053281ac888d1f452"
        },
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          "url": "https://git.kernel.org/stable/c/1fc70b3d513bafb16b17540178870ef46e81c0bb"
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        {
          "url": "https://git.kernel.org/stable/c/3fa110f9e2ea96f567f2194c673c4bc327640111"
        },
        {
          "url": "https://git.kernel.org/stable/c/98c5914d6b7bd4b4675535908e57dea31f1efd6a"
        },
        {
          "url": "https://git.kernel.org/stable/c/f09ac5682f1bb67981fcb6ead4d3cfe439225876"
        },
        {
          "url": "https://git.kernel.org/stable/c/6bcd76c134c55c697148acb5c0194e9666abdf84"
        }
      ],
      "title": "af_packet: Don\u0027t send zero-byte data in tpacket_snd().",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80742",
    "datePublished": "2026-09-03T08:26:25.920Z",
    "dateReserved": "2026-08-26T14:34:25.790Z",
    "dateUpdated": "2026-09-03T08:26:25.920Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
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      "date": "2026-09-21",
      "epss": "0.0021",
      "percentile": "0.11542"
    },
    "microsoft_vex": {
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      "cve": "CVE-2026-80742",
      "id": "msrc_CVE-2026-80742",
      "initial_release_date": "2026-09-04T01:04:39.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "af_packet: Don\u0027t send zero-byte data in tpacket_snd().",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-80742.json",
      "version": "1"
    },
    "nvd": {
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\naf_packet: Don\u0027t send zero-byte data in tpacket_snd().\n\nsyzbot reported a WARNING in __dev_queue_xmit() triggered via tpacket_snd():\n\nskb_assert_len\nWARNING: at include/linux/skbuff.h:2753 skb_assert_len\nWARNING: at __dev_queue_xmit+0x21bc/0x4970 net/core/dev.c:4781\n\nCall Trace:\n \u003cTASK\u003e\n dev_queue_xmit include/linux/netdevice.h:3448 [inline]\n packet_xmit+0x243/0x310 net/packet/af_packet.c:276\n tpacket_snd net/packet/af_packet.c:2907 [inline]\n packet_sendmsg+0x28d6/0x4eb0 net/packet/af_packet.c:3134\n\nWhen sending 0-byte packets via TPACKET ring buffer on devices with no\nhard header (e.g. dev-\u003ehard_header_len == 0), tpacket_fill_skb()\npopulates an skb with skb-\u003elen == 0 and returns 0. tpacket_snd() then\nforwards this empty skb to packet_xmit(), causing __dev_queue_xmit() to\nhit skb_assert_len(skb).\n\nSimilar checks exist in packet_snd() via commit dc633700f00f\n(\"net/af_packet: check len when min_header_len equals to 0\") and in\npacket_sendmsg_spkt() via commit 6a341729fb31 (\"af_packet: Don\u0027t send\nzero-byte data in packet_sendmsg_spkt().\").\n\nReturn -EINVAL in tpacket_fill_skb() when skb-\u003elen is zero to reject\nzero-length packets in tpacket_snd()."
          }
        ],
        "id": "CVE-2026-80742",
        "lastModified": "2026-09-03T13:06:13.437",
        "metrics": {},
        "published": "2026-09-03T13:06:13.437",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/1fc70b3d513bafb16b17540178870ef46e81c0bb"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/3fa110f9e2ea96f567f2194c673c4bc327640111"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/6bcd76c134c55c697148acb5c0194e9666abdf84"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/7521e691c7c4f2231634c95053281ac888d1f452"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/80a702964467b998d254f16cc61c2c9a20540c9d"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/98c5914d6b7bd4b4675535908e57dea31f1efd6a"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/dde212f8622f5cb36223fff1ebd6e6f2a3dc61fe"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/f09ac5682f1bb67981fcb6ead4d3cfe439225876"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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  • 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.