CVE-2025-21961 (GCVE-0-2025-21961)

Vulnerability from cvelistv5 – Published: 2025-04-01 15:46 – Updated: 2026-08-05 11:55
VLAI
Title
eth: bnxt: fix truesize for mb-xdp-pass case
Summary
In the Linux kernel, the following vulnerability has been resolved: eth: bnxt: fix truesize for mb-xdp-pass case When mb-xdp is set and return is XDP_PASS, packet is converted from xdp_buff to sk_buff with xdp_update_skb_shared_info() in bnxt_xdp_build_skb(). bnxt_xdp_build_skb() passes incorrect truesize argument to xdp_update_skb_shared_info(). The truesize is calculated as BNXT_RX_PAGE_SIZE * sinfo->nr_frags but the skb_shared_info was wiped by napi_build_skb() before. So it stores sinfo->nr_frags before bnxt_xdp_build_skb() and use it instead of getting skb_shared_info from xdp_get_shared_info_from_buff(). Splat looks like: ------------[ cut here ]------------ WARNING: CPU: 2 PID: 0 at net/core/skbuff.c:6072 skb_try_coalesce+0x504/0x590 Modules linked in: xt_nat xt_tcpudp veth af_packet xt_conntrack nft_chain_nat xt_MASQUERADE nf_conntrack_netlink xfrm_user xt_addrtype nft_coms CPU: 2 UID: 0 PID: 0 Comm: swapper/2 Not tainted 6.14.0-rc2+ #3 RIP: 0010:skb_try_coalesce+0x504/0x590 Code: 4b fd ff ff 49 8b 34 24 40 80 e6 40 0f 84 3d fd ff ff 49 8b 74 24 48 40 f6 c6 01 0f 84 2e fd ff ff 48 8d 4e ff e9 25 fd ff ff <0f> 0b e99 RSP: 0018:ffffb62c4120caa8 EFLAGS: 00010287 RAX: 0000000000000003 RBX: ffffb62c4120cb14 RCX: 0000000000000ec0 RDX: 0000000000001000 RSI: ffffa06e5d7dc000 RDI: 0000000000000003 RBP: ffffa06e5d7ddec0 R08: ffffa06e6120a800 R09: ffffa06e7a119900 R10: 0000000000002310 R11: ffffa06e5d7dcec0 R12: ffffe4360575f740 R13: ffffe43600000000 R14: 0000000000000002 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffffa0755f700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f147b76b0f8 CR3: 00000001615d4000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: <IRQ> ? __warn+0x84/0x130 ? skb_try_coalesce+0x504/0x590 ? report_bug+0x18a/0x1a0 ? handle_bug+0x53/0x90 ? exc_invalid_op+0x14/0x70 ? asm_exc_invalid_op+0x16/0x20 ? skb_try_coalesce+0x504/0x590 inet_frag_reasm_finish+0x11f/0x2e0 ip_defrag+0x37a/0x900 ip_local_deliver+0x51/0x120 ip_sublist_rcv_finish+0x64/0x70 ip_sublist_rcv+0x179/0x210 ip_list_rcv+0xf9/0x130 How to reproduce: <Node A> ip link set $interface1 xdp obj xdp_pass.o ip link set $interface1 mtu 9000 up ip a a 10.0.0.1/24 dev $interface1 <Node B> ip link set $interfac2 mtu 9000 up ip a a 10.0.0.2/24 dev $interface2 ping 10.0.0.1 -s 65000 Following ping.py patch adds xdp-mb-pass case. so ping.py is going to be able to reproduce this issue.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-10-01 17:15 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 , < 19107e71be330dbccb9f8f9f4cf0a9abeadad802 (git)
Affected: 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 , < b4679807c6083ade4d47f03f80da891afcb6ef62 (git)
Affected: 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 , < 9f7b2aa5034e24d3c49db73d5f760c0435fe31c2 (git)
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Linux Linux Affected: 5.19
Unaffected: 0 , < 5.19 (semver)
Unaffected: 6.12.20 , ≤ 6.12.* (semver)
Unaffected: 6.13.8 , ≤ 6.13.* (semver)
Unaffected: 6.14 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\neth: bnxt: fix truesize for mb-xdp-pass case\n\nWhen mb-xdp is set and return is XDP_PASS, packet is converted from\nxdp_buff to sk_buff with xdp_update_skb_shared_info() in\nbnxt_xdp_build_skb().\nbnxt_xdp_build_skb() passes incorrect truesize argument to\nxdp_update_skb_shared_info().\nThe truesize is calculated as BNXT_RX_PAGE_SIZE * sinfo-\u003enr_frags but\nthe skb_shared_info was wiped by napi_build_skb() before.\nSo it stores sinfo-\u003enr_frags before bnxt_xdp_build_skb() and use it\ninstead of getting skb_shared_info from xdp_get_shared_info_from_buff().\n\nSplat looks like:\n ------------[ cut here ]------------\n WARNING: CPU: 2 PID: 0 at net/core/skbuff.c:6072 skb_try_coalesce+0x504/0x590\n Modules linked in: xt_nat xt_tcpudp veth af_packet xt_conntrack nft_chain_nat xt_MASQUERADE nf_conntrack_netlink xfrm_user xt_addrtype nft_coms\n CPU: 2 UID: 0 PID: 0 Comm: swapper/2 Not tainted 6.14.0-rc2+ #3\n RIP: 0010:skb_try_coalesce+0x504/0x590\n Code: 4b fd ff ff 49 8b 34 24 40 80 e6 40 0f 84 3d fd ff ff 49 8b 74 24 48 40 f6 c6 01 0f 84 2e fd ff ff 48 8d 4e ff e9 25 fd ff ff \u003c0f\u003e 0b e99\n RSP: 0018:ffffb62c4120caa8 EFLAGS: 00010287\n RAX: 0000000000000003 RBX: ffffb62c4120cb14 RCX: 0000000000000ec0\n RDX: 0000000000001000 RSI: ffffa06e5d7dc000 RDI: 0000000000000003\n RBP: ffffa06e5d7ddec0 R08: ffffa06e6120a800 R09: ffffa06e7a119900\n R10: 0000000000002310 R11: ffffa06e5d7dcec0 R12: ffffe4360575f740\n R13: ffffe43600000000 R14: 0000000000000002 R15: 0000000000000002\n FS:  0000000000000000(0000) GS:ffffa0755f700000(0000) knlGS:0000000000000000\n CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007f147b76b0f8 CR3: 00000001615d4000 CR4: 00000000007506f0\n PKRU: 55555554\n Call Trace:\n  \u003cIRQ\u003e\n  ? __warn+0x84/0x130\n  ? skb_try_coalesce+0x504/0x590\n  ? report_bug+0x18a/0x1a0\n  ? handle_bug+0x53/0x90\n  ? exc_invalid_op+0x14/0x70\n  ? asm_exc_invalid_op+0x16/0x20\n  ? skb_try_coalesce+0x504/0x590\n  inet_frag_reasm_finish+0x11f/0x2e0\n  ip_defrag+0x37a/0x900\n  ip_local_deliver+0x51/0x120\n  ip_sublist_rcv_finish+0x64/0x70\n  ip_sublist_rcv+0x179/0x210\n  ip_list_rcv+0xf9/0x130\n\nHow to reproduce:\n\u003cNode A\u003e\nip link set $interface1 xdp obj xdp_pass.o\nip link set $interface1 mtu 9000 up\nip a a 10.0.0.1/24 dev $interface1\n\u003cNode B\u003e\nip link set $interfac2 mtu 9000 up\nip a a 10.0.0.2/24 dev $interface2\nping 10.0.0.1 -s 65000\n\nFollowing ping.py patch adds xdp-mb-pass case. so ping.py is going to be\nable to reproduce this issue."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: eth: bnxt: correcci\u00f3n de truesize para el caso mb-xdp-pass. Cuando mb-xdp est\u00e1 configurado y el valor de retorno es XDP_PASS, el paquete se convierte de xdp_buff a sk_buff con xdp_update_skb_shared_info() en bnxt_xdp_build_skb(). bnxt_xdp_build_skb() pasa un argumento truesize incorrecto a xdp_update_skb_shared_info(). El truesize se calcula como BNXT_RX_PAGE_SIZE * sinfo-\u0026gt;nr_frags, pero napi_build_skb() borr\u00f3 previamente skb_shared_info. De este modo, almacena sinfo-\u0026gt;nr_frags antes de bnxt_xdp_build_skb() y lo utiliza en lugar de obtener skb_shared_info de xdp_get_shared_info_from_buff(). El splat se ve as\u00ed: ------------[ cortar aqu\u00ed ]------------ ADVERTENCIA: CPU: 2 PID: 0 en net/core/skbuff.c:6072 skb_try_coalesce+0x504/0x590 M\u00f3dulos enlazados en: xt_nat xt_tcpudp veth af_packet xt_conntrack nft_chain_nat xt_MASQUERADE nf_conntrack_netlink xfrm_user xt_addrtype nft_coms CPU: 2 UID: 0 PID: 0 Comm: swapper/2 No contaminado 6.14.0-rc2+ #3 RIP: 0010:skb_try_coalesce+0x504/0x590 C\u00f3digo: 4b fd ff ff 49 8b 34 24 40 80 e6 40 0f 84 3d fd ff ff 49 8b 74 24 48 40 f6 c6 01 0f 84 2e fd ff ff 48 8d 4e ff e9 25 fd ff ff \u0026lt;0f\u0026gt; 0b e99 RSP: 0018:ffffb62c4120caa8 EFLAGS: 00010287 RAX: 000000000000003 RBX: ffffb62c4120cb14 RCX: 0000000000000ec0 RDX: 0000000000001000 RSI: ffffa06e5d7dc000 RDI: 000000000000003 RBP: ffffa06e5d7ddec0 R08: ffffa06e6120a800 R09: ffffa06e7a119900 R10: 0000000000002310 R11: ffffa06e5d7dcec0 R12: ffffe4360575f740 R13: ffffe43600000000 R14: 000000000000002 R15: 0000000000000002 FS: 000000000000000(0000) GS:ffffa0755f700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f147b76b0f8 CR3: 00000001615d4000 CR4: 00000000007506f0 PKRU: 55555554 Rastreo de llamadas:  ? __warn+0x84/0x130 ? skb_try_coalesce+0x504/0x590 ? report_bug+0x18a/0x1a0 ? handle_bug+0x53/0x90 ? exc_invalid_op+0x14/0x70 ? asm_exc_invalid_op+0x16/0x20 ? skb_try_coalesce+0x504/0x590 inet_frag_reasm_finish+0x11f/0x2e0 ip_defrag+0x37a/0x900 ip_local_deliver+0x51/0x120 ip_sublist_rcv_finish+0x64/0x70 ip_sublist_rcv+0x179/0x210 ip_list_rcv+0xf9/0x130 C\u00f3mo reproducir:  enlace ip establecido $interfaz1 xdp obj xdp_pass.o enlace ip establecido $interfaz1 mtu 9000 activo ip aa 10.0.0.1/24 dev $interfaz1  enlace ip establecido $interfaz2 mtu 9000 activo ip aa 10.0.0.2/24 El siguiente parche de ping.py agrega el caso xdp-mb-pass, por lo que ping.py podr\u00e1 reproducir este problema."
          }
        ],
        "id": "CVE-2025-21961",
        "lastModified": "2026-07-30T06:21:59.883",
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        "published": "2025-04-01T16:15:27.343",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
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      "title": "kernel: eth: bnxt: fix truesize for mb-xdp-pass case",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-21961.json",
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      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-21961.json",
      "version": "49"
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            "providerMetadata": {
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        "cna": {
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              "product": "Linux",
              "programFiles": [
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              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\neth: bnxt: fix truesize for mb-xdp-pass case\n\nWhen mb-xdp is set and return is XDP_PASS, packet is converted from\nxdp_buff to sk_buff with xdp_update_skb_shared_info() in\nbnxt_xdp_build_skb().\nbnxt_xdp_build_skb() passes incorrect truesize argument to\nxdp_update_skb_shared_info().\nThe truesize is calculated as BNXT_RX_PAGE_SIZE * sinfo-\u003enr_frags but\nthe skb_shared_info was wiped by napi_build_skb() before.\nSo it stores sinfo-\u003enr_frags before bnxt_xdp_build_skb() and use it\ninstead of getting skb_shared_info from xdp_get_shared_info_from_buff().\n\nSplat looks like:\n ------------[ cut here ]------------\n WARNING: CPU: 2 PID: 0 at net/core/skbuff.c:6072 skb_try_coalesce+0x504/0x590\n Modules linked in: xt_nat xt_tcpudp veth af_packet xt_conntrack nft_chain_nat xt_MASQUERADE nf_conntrack_netlink xfrm_user xt_addrtype nft_coms\n CPU: 2 UID: 0 PID: 0 Comm: swapper/2 Not tainted 6.14.0-rc2+ #3\n RIP: 0010:skb_try_coalesce+0x504/0x590\n Code: 4b fd ff ff 49 8b 34 24 40 80 e6 40 0f 84 3d fd ff ff 49 8b 74 24 48 40 f6 c6 01 0f 84 2e fd ff ff 48 8d 4e ff e9 25 fd ff ff \u003c0f\u003e 0b e99\n RSP: 0018:ffffb62c4120caa8 EFLAGS: 00010287\n RAX: 0000000000000003 RBX: ffffb62c4120cb14 RCX: 0000000000000ec0\n RDX: 0000000000001000 RSI: ffffa06e5d7dc000 RDI: 0000000000000003\n RBP: ffffa06e5d7ddec0 R08: ffffa06e6120a800 R09: ffffa06e7a119900\n R10: 0000000000002310 R11: ffffa06e5d7dcec0 R12: ffffe4360575f740\n R13: ffffe43600000000 R14: 0000000000000002 R15: 0000000000000002\n FS:  0000000000000000(0000) GS:ffffa0755f700000(0000) knlGS:0000000000000000\n CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007f147b76b0f8 CR3: 00000001615d4000 CR4: 00000000007506f0\n PKRU: 55555554\n Call Trace:\n  \u003cIRQ\u003e\n  ? __warn+0x84/0x130\n  ? skb_try_coalesce+0x504/0x590\n  ? report_bug+0x18a/0x1a0\n  ? handle_bug+0x53/0x90\n  ? exc_invalid_op+0x14/0x70\n  ? asm_exc_invalid_op+0x16/0x20\n  ? skb_try_coalesce+0x504/0x590\n  inet_frag_reasm_finish+0x11f/0x2e0\n  ip_defrag+0x37a/0x900\n  ip_local_deliver+0x51/0x120\n  ip_sublist_rcv_finish+0x64/0x70\n  ip_sublist_rcv+0x179/0x210\n  ip_list_rcv+0xf9/0x130\n\nHow to reproduce:\n\u003cNode A\u003e\nip link set $interface1 xdp obj xdp_pass.o\nip link set $interface1 mtu 9000 up\nip a a 10.0.0.1/24 dev $interface1\n\u003cNode B\u003e\nip link set $interfac2 mtu 9000 up\nip a a 10.0.0.2/24 dev $interface2\nping 10.0.0.1 -s 65000\n\nFollowing ping.py patch adds xdp-mb-pass case. so ping.py is going to be\nable to reproduce this issue."
            }
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              "scenarios": [
                {
                  "lang": "en",
                  "value": "AV:N - The bug is triggered entirely by an inbound Ethernet frame processed in the bnxt_en NAPI receive path (bnxt_rx_pkt \u2192 bnxt_xdp_build_skb), with the splat landing in ip_defrag()/skb_try_coalesce(); no local access to the target is required. Jumbo/multi-buffer frames are routable end-to-end inside jumbo-enabled datacenter and cloud VPC fabrics, so the sender need not share the victim\u0027s L2 segment.\nAC:L - On an affected host (Broadcom NetXtreme NIC, jumbo MTU, multi-buffer XDP program returning XDP_PASS) every oversized packet deterministically produces the wrong truesize \u2014 the upstream reproducer is a single `ping -s 65000`. There is no race to win and no memory-layout condition outside the attacker\u0027s control.\nPR:N - The vulnerable code executes in softirq/NAPI context on raw received frames, long before any socket lookup, authentication, or capability check. An unauthenticated attacker with no account on the target simply emits packets.\nUI:N - No victim action is needed at attack time; the XDP program and jumbo MTU are pre-existing deployment configuration, not interaction solicited from a user. Packet arrival alone drives the entire path.\nS:U - The miscounted truesize corrupts skb and socket memory accounting within the same kernel security authority that owns the RX path. No VM, container, or IOMMU boundary is crossed.\nC:N - Only the truesize accounting field is wrong; skb-\u003efrags[] and xdp_frags_size retain their correct values, so no out-of-bounds or uninitialized memory is read or exposed to userspace. Nothing is disclosed to the attacker.\nI:N - There is no out-of-bounds write, type confusion, or control-flow corruption \u2014 the erroneous value only skews internal memory-accounting counters, whose consequence is availability rather than data modification.\nA:H - The under-counted truesize trips WARN_ON_ONCE(delta \u003c len) in skb_try_coalesce() during IP reassembly, which is an immediate kernel panic on the panic_on_warn configurations common in cloud and hardened fleets. Even without panic_on_warn, sk_rmem_alloc/sk_forward_alloc and the IP-defrag memory limit are under-charged by roughly the frag count, letting a remote flood pin several times the configured buffer memory and drive the system to OOM."
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            },
            {
              "url": "https://git.kernel.org/stable/c/9f7b2aa5034e24d3c49db73d5f760c0435fe31c2"
            }
          ],
          "title": "eth: bnxt: fix truesize for mb-xdp-pass case",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2025-21961",
        "datePublished": "2025-04-01T15:46:58.795Z",
        "dateReserved": "2024-12-29T08:45:45.795Z",
        "dateUpdated": "2026-08-05T11:55:40.073Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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Taxonomy of the tags.





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

Author Source Type Date Other

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.



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.