{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-31503", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.105Z", "datePublished": "2026-04-22T13:54:23.221Z", "dateUpdated": "2026-04-22T13:54:23.221Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-04-22T13:54:23.221Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nudp: Fix wildcard bind conflict check when using hash2\n\nWhen binding a udp_sock to a local address and port, UDP uses\ntwo hashes (udptable->hash and udptable->hash2) for collision\ndetection. The current code switches to \"hash2\" when\nhslot->count > 10.\n\n\"hash2\" is keyed by local address and local port.\n\"hash\" is keyed by local port only.\n\nThe issue can be shown in the following bind sequence (pseudo code):\n\nbind(fd1, \"[fd00::1]:8888\")\nbind(fd2, \"[fd00::2]:8888\")\nbind(fd3, \"[fd00::3]:8888\")\nbind(fd4, \"[fd00::4]:8888\")\nbind(fd5, \"[fd00::5]:8888\")\nbind(fd6, \"[fd00::6]:8888\")\nbind(fd7, \"[fd00::7]:8888\")\nbind(fd8, \"[fd00::8]:8888\")\nbind(fd9, \"[fd00::9]:8888\")\nbind(fd10, \"[fd00::10]:8888\")\n\n/* Correctly return -EADDRINUSE because \"hash\" is used\n * instead of \"hash2\". udp_lib_lport_inuse() detects the\n * conflict.\n */\nbind(fail_fd, \"[::]:8888\")\n\n/* After one more socket is bound to \"[fd00::11]:8888\",\n * hslot->count exceeds 10 and \"hash2\" is used instead.\n */\nbind(fd11, \"[fd00::11]:8888\")\nbind(fail_fd, \"[::]:8888\") /* succeeds unexpectedly */\n\nThe same issue applies to the IPv4 wildcard address \"0.0.0.0\"\nand the IPv4-mapped wildcard address \"::ffff:0.0.0.0\". For\nexample, if there are existing sockets bound to\n\"192.168.1.[1-11]:8888\", then binding \"0.0.0.0:8888\" or\n\"[::ffff:0.0.0.0]:8888\" can also miss the conflict when\nhslot->count > 10.\n\nTCP inet_csk_get_port() already has the correct check in\ninet_use_bhash2_on_bind(). Rename it to\ninet_use_hash2_on_bind() and move it to inet_hashtables.h\nso udp.c can reuse it in this fix."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/net/inet_hashtables.h", "net/ipv4/inet_connection_sock.c", "net/ipv4/udp.c"], "versions": [{"version": "30fff9231fad757c061285e347b33c5149c2c2e4", "lessThan": "d6ace0dbcbb7fd285738bb87b42b71b01858c952", "status": "affected", "versionType": "git"}, {"version": "30fff9231fad757c061285e347b33c5149c2c2e4", "lessThan": "2297e38114316b26ae02f2d205c49b5511c5ed55", "status": "affected", "versionType": "git"}, {"version": "30fff9231fad757c061285e347b33c5149c2c2e4", "lessThan": "f1bed05a832ae79be5f7a105da56810eaa59a5f1", "status": "affected", "versionType": "git"}, {"version": "30fff9231fad757c061285e347b33c5149c2c2e4", "lessThan": "18d84c45def3671d5c89fbdd5d4ab8a3217fe4b4", "status": "affected", "versionType": "git"}, {"version": "30fff9231fad757c061285e347b33c5149c2c2e4", "lessThan": "0a360f7f73a06ac88f18917055fbcc79694252d7", "status": "affected", "versionType": "git"}, {"version": "30fff9231fad757c061285e347b33c5149c2c2e4", "lessThan": "e537dd15d0d4ad989d56a1021290f0c674dd8b28", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/net/inet_hashtables.h", "net/ipv4/inet_connection_sock.c", "net/ipv4/udp.c"], "versions": [{"version": "2.6.33", "status": "affected"}, {"version": "0", "lessThan": "2.6.33", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.168", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.131", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.80", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.21", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19.11", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0", "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": "2.6.33", "versionEndExcluding": "6.1.168"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.6.131"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.12.80"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.18.21"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.19.11"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "7.0"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/d6ace0dbcbb7fd285738bb87b42b71b01858c952"}, {"url": "https://git.kernel.org/stable/c/2297e38114316b26ae02f2d205c49b5511c5ed55"}, {"url": "https://git.kernel.org/stable/c/f1bed05a832ae79be5f7a105da56810eaa59a5f1"}, {"url": "https://git.kernel.org/stable/c/18d84c45def3671d5c89fbdd5d4ab8a3217fe4b4"}, {"url": "https://git.kernel.org/stable/c/0a360f7f73a06ac88f18917055fbcc79694252d7"}, {"url": "https://git.kernel.org/stable/c/e537dd15d0d4ad989d56a1021290f0c674dd8b28"}], "title": "udp: Fix wildcard bind conflict check when using hash2", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nudp: Fix wildcard bind conflict check when using hash2\n\nWhen binding a udp_sock to a local address and port, UDP uses\ntwo hashes (udptable->hash and udptable->hash2) for collision\ndetection. The current code switches to \"hash2\" when\nhslot->count > 10.\n\n\"hash2\" is keyed by local address and local port.\n\"hash\" is keyed by local port only.\n\nThe issue can be shown in the following bind sequence (pseudo code):\n\nbind(fd1, \"[fd00::1]:8888\")\nbind(fd2, \"[fd00::2]:8888\")\nbind(fd3, \"[fd00::3]:8888\")\nbind(fd4, \"[fd00::4]:8888\")\nbind(fd5, \"[fd00::5]:8888\")\nbind(fd6, \"[fd00::6]:8888\")\nbind(fd7, \"[fd00::7]:8888\")\nbind(fd8, \"[fd00::8]:8888\")\nbind(fd9, \"[fd00::9]:8888\")\nbind(fd10, \"[fd00::10]:8888\")\n\n/* Correctly return -EADDRINUSE because \"hash\" is used\n * instead of \"hash2\". udp_lib_lport_inuse() detects the\n * conflict.\n */\nbind(fail_fd, \"[::]:8888\")\n\n/* After one more socket is bound to \"[fd00::11]:8888\",\n * hslot->count exceeds 10 and \"hash2\" is used instead.\n */\nbind(fd11, \"[fd00::11]:8888\")\nbind(fail_fd, \"[::]:8888\") /* succeeds unexpectedly */\n\nThe same issue applies to the IPv4 wildcard address \"0.0.0.0\"\nand the IPv4-mapped wildcard address \"::ffff:0.0.0.0\". For\nexample, if there are existing sockets bound to\n\"192.168.1.[1-11]:8888\", then binding \"0.0.0.0:8888\" or\n\"[::ffff:0.0.0.0]:8888\" can also miss the conflict when\nhslot->count > 10.\n\nTCP inet_csk_get_port() already has the correct check in\ninet_use_bhash2_on_bind(). Rename it to\ninet_use_hash2_on_bind() and move it to inet_hashtables.h\nso udp.c can reuse it in this fix."}], "id": "CVE-2026-31503", "lastModified": "2026-04-22T14:16:48.863", "metrics": {}, "published": "2026-04-22T14:16:48.863", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0a360f7f73a06ac88f18917055fbcc79694252d7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/18d84c45def3671d5c89fbdd5d4ab8a3217fe4b4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2297e38114316b26ae02f2d205c49b5511c5ed55"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d6ace0dbcbb7fd285738bb87b42b71b01858c952"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e537dd15d0d4ad989d56a1021290f0c674dd8b28"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f1bed05a832ae79be5f7a105da56810eaa59a5f1"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: udp: Fix wildcard bind conflict check when using hash2", "id": "2460736", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2460736"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-253", "details": ["A flaw was found in the Linux kernel's User Datagram Protocol (UDP) implementation. When a significant number of UDP sockets are bound to specific local addresses on the same port, the kernel's conflict detection mechanism can fail. This allows a local attacker to bind to a wildcard address on a port that should already be in use, potentially leading to a Denial of Service (DoS) for legitimate applications attempting to use that port."], "name": "CVE-2026-31503", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-04-22T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-31503\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-31503\nhttps://lore.kernel.org/linux-cve-announce/2026042206-CVE-2026-31503-602a@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[30fff9231fad757c061285e347b33c5149c2c2e4,d6ace0dbcbb7fd285738bb87b42b71b01858c952)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[30fff9231fad757c061285e347b33c5149c2c2e4,2297e38114316b26ae02f2d205c49b5511c5ed55)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[30fff9231fad757c061285e347b33c5149c2c2e4,f1bed05a832ae79be5f7a105da56810eaa59a5f1)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[30fff9231fad757c061285e347b33c5149c2c2e4,18d84c45def3671d5c89fbdd5d4ab8a3217fe4b4)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[30fff9231fad757c061285e347b33c5149c2c2e4,0a360f7f73a06ac88f18917055fbcc79694252d7)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[30fff9231fad757c061285e347b33c5149c2c2e4,e537dd15d0d4ad989d56a1021290f0c674dd8b28)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "2.6.33"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,2.6.33)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.168,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.131,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.80,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.21,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.19.11,6.20.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.0,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-04-22T18:00:05.277219+00:00", "updated": "2026-04-22T18:00:05.277291+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}