{"id":"CVE-2025-38591","state":"PUBLISHED","title":"bpf: Reject narrower access to pointer ctx fields","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject narrower access to pointer ctx fields\n\nThe following BPF program, simplified from a syzkaller repro, causes a\nkernel warning:\n\n    r0 = *(u8 *)(r1 + 169);\n    exit;\n\nWith pointer field sk being at offset 168 in __sk_buff. This access is\ndetected as a narrower read in bpf_skb_is_valid_access because it\ndoesn't match offsetof(struct __sk_buff, sk). It is therefore allowed\nand later proceeds to bpf_convert_ctx_access. Note that for the\n\"is_narrower_load\" case in the convert_ctx_accesses(), the insn->off\nis aligned, so the cnt may not be 0 because it matches the\noffsetof(struct __sk_buff, sk) in the bpf_convert_ctx_access. However,\nthe target_size stays 0 and the verifier errors with a kernel warning:\n\n    verifier bug: error during ctx access conversion(1)\n\nThis patch fixes that to return a proper \"invalid bpf_context access\noff=X size=Y\" error on the load instruction.\n\nThe same issue affects multiple other fields in context structures that\nallow narrow access. Some other non-affected fields (for sk_msg,\nsk_lookup, and sockopt) were also changed to use bpf_ctx_range_ptr for\nconsistency.\n\nNote this syzkaller crash was reported in the \"Closes\" link below, which\nused to be about a different bug, fixed in\ncommit fce7bd8e385a (\"bpf/verifier: Handle BPF_LOAD_ACQ instructions\nin insn_def_regno()\"). Because syzbot somehow confused the two bugs,\nthe new crash and repro didn't get reported to the mailing list.","publishedAt":"2025-08-19T17:03:12.508Z","updatedAt":"2026-10-15T01:07:31.830Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"7847c4140e06f6e87229faae22cc38525334c156","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"feae34c992eb7191862fb1594c704fbbf650fef8","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"33660d44e789edb4f303210c813fc56d56377a90","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"e2e9599f3503df7cf3569d2b6c50d5488fb59435","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"058a0da4f6d916a79b693384111bb80a90d73763","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"202900ceeef67458c964c2af6e1427c8e533ea7c","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"e09299225d5ba3916c91ef70565f7d2187e4cca0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/cgroup.c","net/core/filter.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.13","versionType":"semver"},{"version":"5.10.249","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.199","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.162","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.67","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.16.1","status":"unaffected","lessThanOrEqual":"6.16.*","versionType":"semver"},{"version":"6.17","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/cgroup.c","net/core/filter.c"]}],"references":["https://git.kernel.org/stable/c/7847c4140e06f6e87229faae22cc38525334c156","https://git.kernel.org/stable/c/feae34c992eb7191862fb1594c704fbbf650fef8","https://git.kernel.org/stable/c/33660d44e789edb4f303210c813fc56d56377a90","https://git.kernel.org/stable/c/e2e9599f3503df7cf3569d2b6c50d5488fb59435","https://git.kernel.org/stable/c/058a0da4f6d916a79b693384111bb80a90d73763","https://git.kernel.org/stable/c/202900ceeef67458c964c2af6e1427c8e533ea7c","https://git.kernel.org/stable/c/e09299225d5ba3916c91ef70565f7d2187e4cca0","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:09.358Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/38xxx/CVE-2025-38591.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-38591","state":"PUBLISHED","datePublished":"2025-08-19T17:03:12.508Z","dateUpdated":"2026-10-15T01:07:31.830Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T04:51:24.026Z"},"containers":{"cna":{"title":"bpf: Reject narrower access to pointer ctx fields","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject narrower access to pointer ctx fields\n\nThe following BPF program, simplified from a syzkaller repro, causes a\nkernel warning:\n\n    r0 = *(u8 *)(r1 + 169);\n    exit;\n\nWith pointer field sk being at offset 168 in __sk_buff. This access is\ndetected as a narrower read in bpf_skb_is_valid_access because it\ndoesn't match offsetof(struct __sk_buff, sk). It is therefore allowed\nand later proceeds to bpf_convert_ctx_access. Note that for the\n\"is_narrower_load\" case in the convert_ctx_accesses(), the insn->off\nis aligned, so the cnt may not be 0 because it matches the\noffsetof(struct __sk_buff, sk) in the bpf_convert_ctx_access. However,\nthe target_size stays 0 and the verifier errors with a kernel warning:\n\n    verifier bug: error during ctx access conversion(1)\n\nThis patch fixes that to return a proper \"invalid bpf_context access\noff=X size=Y\" error on the load instruction.\n\nThe same issue affects multiple other fields in context structures that\nallow narrow access. Some other non-affected fields (for sk_msg,\nsk_lookup, and sockopt) were also changed to use bpf_ctx_range_ptr for\nconsistency.\n\nNote this syzkaller crash was reported in the \"Closes\" link below, which\nused to be about a different bug, fixed in\ncommit fce7bd8e385a (\"bpf/verifier: Handle BPF_LOAD_ACQ instructions\nin insn_def_regno()\"). Because syzbot somehow confused the two bugs,\nthe new crash and repro didn't get reported to the mailing list."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"7847c4140e06f6e87229faae22cc38525334c156","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"feae34c992eb7191862fb1594c704fbbf650fef8","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"33660d44e789edb4f303210c813fc56d56377a90","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"e2e9599f3503df7cf3569d2b6c50d5488fb59435","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"058a0da4f6d916a79b693384111bb80a90d73763","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"202900ceeef67458c964c2af6e1427c8e533ea7c","versionType":"git"},{"version":"f96da09473b52c09125cc9bf7d7d4576ae8229e0","status":"affected","lessThan":"e09299225d5ba3916c91ef70565f7d2187e4cca0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/cgroup.c","net/core/filter.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.13","versionType":"semver"},{"version":"5.10.249","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.199","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.162","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.67","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.16.1","status":"unaffected","lessThanOrEqual":"6.16.*","versionType":"semver"},{"version":"6.17","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/cgroup.c","net/core/filter.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/7847c4140e06f6e87229faae22cc38525334c156"},{"url":"https://git.kernel.org/stable/c/feae34c992eb7191862fb1594c704fbbf650fef8"},{"url":"https://git.kernel.org/stable/c/33660d44e789edb4f303210c813fc56d56377a90"},{"url":"https://git.kernel.org/stable/c/e2e9599f3503df7cf3569d2b6c50d5488fb59435"},{"url":"https://git.kernel.org/stable/c/058a0da4f6d916a79b693384111bb80a90d73763"},{"url":"https://git.kernel.org/stable/c/202900ceeef67458c964c2af6e1427c8e533ea7c"},{"url":"https://git.kernel.org/stable/c/e09299225d5ba3916c91ef70565f7d2187e4cca0"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-09-14T11:58:03.288Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"5.10.249"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"5.15.199"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"6.1.162"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"6.12.67"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"6.16.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"6.17"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2025-38591","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-06-10T20:41:20.077651Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-11T18:44:11.247Z"}},{"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIPLUS S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.6","status":"affected","lessThan":"*","versionType":"custom"}]},{"vendor":"Siemens","product":"SIPLUS S7-1500 CPU 1518-4 PN/DP MFP","defaultStatus":"unknown","versions":[{"version":"V3.1.7","status":"affected","lessThan":"*","versionType":"custom"}]}],"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-457936.html"}],"providerMetadata":{"shortName":"siemens-SADP","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","dateUpdated":"2026-10-15T01:07:31.830Z"},"x_adpType":"supplier"}]}}}