{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90067","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.784Z","datePublished":"2026-09-17T16:05:49.600Z","dateUpdated":"2026-09-18T17:52:51.640Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-18T17:52:51.640Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: validate banner payload length\n\nWhen parsing the Ceph messenger v2 protocol banner, the `payload_len` field\nis decoded from the banner prefix. If a client sends a banner with a\n`payload_len` of 0, the kernel sets up a 0-length socket read. This\nviolates an invariant in the state machine, triggering a warning in\n`populate_in_iter()`:\n\n------------[ cut here ]------------\n!iov_iter_count(&con->v2.in_iter)\nWARNING: net/ceph/messenger_v2.c:3129 at populate_in_iter\nnet/ceph/messenger_v2.c:3129 [inline], CPU#1: kworker/1:3/5070\nWARNING: net/ceph/messenger_v2.c:3129 at ceph_con_v2_try_read+0x6634/0x6810\nnet/ceph/messenger_v2.c:3159, CPU#1: kworker/1:3/5070\n...\nCall Trace:\n <TASK>\n ceph_con_workfn+0x1f5/0x14a0 net/ceph/messenger.c:1575\n process_one_work kernel/workqueue.c:3322 [inline]\n process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405\n worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486\n kthread+0x388/0x470 kernel/kthread.c:436\n ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n </TASK>\n\nAccording to the msgr2 protocol specification, the banner payload is\nexpected to contain at least two 64-bit integers (`server_feat` and\n`server_req_feat`). Therefore, `payload_len` must be at least 16 bytes.\n\nFix this by adding a check in `process_banner_prefix()` to reject a\n`payload_len` smaller than 16 bytes. This prevents the 0-length read and\ncorrectly aborts the connection with a protocol error."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The attacker-controlled field is the 16-bit payload_len in the msgr2 banner prefix (\"ceph v2\\n\" plus le16) that process_banner_prefix() decodes from bytes received by ceph_con_v2_try_read() on the TCP socket opened by ceph_tcp_connect() in ceph_con_v2_try_write(); a remote MON/OSD/MDS peer sends that banner over routable IP.\nAC:L - The TCP peer fully controls the banner prefix and can set payload_len to 0, so prepare_read_banner_payload() installs a zero-length in_iter and populate_in_iter() hits WARN_ON(!iov_iter_count(&con->v2.in_iter)) on every such handshake; no race or layout outside the attacker’s control is required.\nPR:N - process_banner_prefix() runs in CEPH_CON_S_V2_BANNER_PREFIX, before prepare_hello() and before CEPH_CON_S_V2_AUTH, so the malformed payload_len is processed prior to Cephx or any other credential check; the attacker is the remote TCP peer and needs no account on the victim host.\nUI:N - Once a kernel CephFS or RBD client is running, __open_session(), reopen_osd(), and MDS ceph_con_open() automatically TCP-reconnect and ceph_con_workfn() reads the peer banner with no further victim action; a compromised cluster daemon triggers the bug on that reconnect.\nS:U - The WARN_ON in populate_in_iter() and the resulting connection fault remain inside the victim kernel’s libceph messenger and do not cross a VM, IOMMU, or sandbox boundary.\nC:N - A zero payload_len only makes populate_in_iter() WARN and return -ENODATA after prepare_read_banner_payload() sets up an empty in_iter; the path does not perform an out-of-bounds read, UAF, or other kernel-memory disclosure.\nI:N - prepare_read_banner_payload() with payload_len 0 never writes past an allocated buffer, and the failure path only faults the connection; attacker input does not corrupt kernel memory or hijack control flow.\nA:H - WARN_ON(!iov_iter_count(&con->v2.in_iter)) in populate_in_iter() after a zero-length banner payload is an attacker-triggerable kernel warning that panics the host when panic_on_warn is set, and the -ENODATA return through ceph_con_v2_try_read() into con_fault() aborts every msgr2 handshake."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ceph/messenger_v2.c"],"versions":[{"version":"cd1a677cad994021b19665ed476aea63f5d54f31","lessThan":"279c0852999fd2384f4a88155091a99e81f96873","status":"affected","versionType":"git"},{"version":"cd1a677cad994021b19665ed476aea63f5d54f31","lessThan":"6cf666e47f2b51d5a887ec8a3226cde951757d27","status":"affected","versionType":"git"},{"version":"cd1a677cad994021b19665ed476aea63f5d54f31","lessThan":"3b2e62a7655d347a845a91155610ddae11daffc6","status":"affected","versionType":"git"},{"version":"cd1a677cad994021b19665ed476aea63f5d54f31","lessThan":"c1b937ff24b19e69aa7fb1b0f46a74d4c9668692","status":"affected","versionType":"git"},{"version":"cd1a677cad994021b19665ed476aea63f5d54f31","lessThan":"6d1c6f228854aa89844fd0152d7ed7ac72a55e89","status":"affected","versionType":"git"},{"version":"cd1a677cad994021b19665ed476aea63f5d54f31","lessThan":"c77633a9595658210a6e216a071e5a396a0835a7","status":"affected","versionType":"git"},{"version":"cd1a677cad994021b19665ed476aea63f5d54f31","lessThan":"f374967fcdf04001c9b66df1c19106fa83cd91f7","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ceph/messenger_v2.c"],"versions":[{"version":"5.11","status":"affected"},{"version":"0","lessThan":"5.11","status":"unaffected","versionType":"semver"},{"version":"5.15.221","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.188","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.157","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.110","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.52","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.6","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"7.3-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/279c0852999fd2384f4a88155091a99e81f96873"},{"url":"https://git.kernel.org/stable/c/6cf666e47f2b51d5a887ec8a3226cde951757d27"},{"url":"https://git.kernel.org/stable/c/3b2e62a7655d347a845a91155610ddae11daffc6"},{"url":"https://git.kernel.org/stable/c/c1b937ff24b19e69aa7fb1b0f46a74d4c9668692"},{"url":"https://git.kernel.org/stable/c/6d1c6f228854aa89844fd0152d7ed7ac72a55e89"},{"url":"https://git.kernel.org/stable/c/c77633a9595658210a6e216a071e5a396a0835a7"},{"url":"https://git.kernel.org/stable/c/f374967fcdf04001c9b66df1c19106fa83cd91f7"}],"title":"libceph: validate banner payload length","x_generator":{"engine":"bippy-1.2.0"}}}}