{"api_version":"1","generated_at":"2026-05-28T15:54:18+00:00","cve":"CVE-2026-45933","urls":{"html":"https://cve.report/CVE-2026-45933","api":"https://cve.report/api/cve/CVE-2026-45933.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-45933","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-45933"},"summary":{"title":"bpf: Preserve id of register in sync_linked_regs()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Preserve id of register in sync_linked_regs()\n\nsync_linked_regs() copies the id of known_reg to reg when propagating\nbounds of known_reg to reg using the off of known_reg, but when\nknown_reg was linked to reg like:\n\nknown_reg = reg         ; both known_reg and reg get same id\nknown_reg += 4          ; known_reg gets off = 4, and its id gets BPF_ADD_CONST\n\nnow when a call to sync_linked_regs() happens, let's say with the following:\n\nif known_reg >= 10 goto pc+2\n\nknown_reg's new bounds are propagated to reg but now reg gets\nBPF_ADD_CONST from the copy.\n\nThis means if another link to reg is created like:\n\nanother_reg = reg       ; another_reg should get the id of reg but\n                          assign_scalar_id_before_mov() sees\n                          BPF_ADD_CONST on reg and assigns a new id to it.\n\nAs reg has a new id now, known_reg's link to reg is broken. If we find\nnew bounds for known_reg, they will not be propagated to reg.\n\nThis can be seen in the selftest added in the next commit:\n\n0: (85) call bpf_get_prandom_u32#7    ; R0=scalar()\n1: (57) r0 &= 255                     ; R0=scalar(smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))\n2: (bf) r1 = r0                       ; R0=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff)) R1=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))\n3: (07) r1 += 4                       ; R1=scalar(id=1+4,smin=umin=smin32=umin32=4,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))\n4: (a5) if r1 < 0xa goto pc+4         ; R1=scalar(id=1+4,smin=umin=smin32=umin32=10,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))\n5: (bf) r2 = r0                       ; R0=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=255) R2=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=255)\n6: (a5) if r1 < 0xe goto pc+2         ; R1=scalar(id=1+4,smin=umin=smin32=umin32=14,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))\n7: (35) if r0 >= 0xa goto pc+1        ; R0=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=9,var_off=(0x0; 0xf))\n8: (37) r0 /= 0\ndiv by zero\n\nWhen 4 is verified, r1's bounds are propagated to r0 but r0 also gets\nBPF_ADD_CONST (bug).\nWhen 5 is verified, r0 gets a new id (2) and its link with r1 is broken.\n\nAfter 6 we know r1 has bounds [14, 259] and therefore r0 should have\nbounds [10, 255], therefore the branch at 7 is always taken. But because\nr0's id was changed to 2, r1's new bounds are not propagated to r0.\nThe verifier still thinks r0 has bounds [6, 255] before 7 and execution\ncan reach div by zero.\n\nFix this by preserving id in sync_linked_regs() like off and subreg_def.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-27 14:17:09","updated_at":"2026-05-27 14:48:03"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/92a8cb1806adefb263cf096eab6705705cf7eee1","name":"https://git.kernel.org/stable/c/92a8cb1806adefb263cf096eab6705705cf7eee1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/58059335e46537de682db84984f7716c813208c4","name":"https://git.kernel.org/stable/c/58059335e46537de682db84984f7716c813208c4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/af9e89d8dd39530c8bd14c33ddf6b502df1071b6","name":"https://git.kernel.org/stable/c/af9e89d8dd39530c8bd14c33ddf6b502df1071b6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/65d114b5270b62aefb820ecd6c3b7caeea8f895d","name":"https://git.kernel.org/stable/c/65d114b5270b62aefb820ecd6c3b7caeea8f895d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-45933","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45933","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 98d7ca374ba4b39e7535613d40e159f09ca14da2 58059335e46537de682db84984f7716c813208c4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 98d7ca374ba4b39e7535613d40e159f09ca14da2 92a8cb1806adefb263cf096eab6705705cf7eee1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 98d7ca374ba4b39e7535613d40e159f09ca14da2 65d114b5270b62aefb820ecd6c3b7caeea8f895d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 98d7ca374ba4b39e7535613d40e159f09ca14da2 af9e89d8dd39530c8bd14c33ddf6b502df1071b6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.11","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.11 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.75 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.14 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.4 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/bpf/verifier.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"58059335e46537de682db84984f7716c813208c4","status":"affected","version":"98d7ca374ba4b39e7535613d40e159f09ca14da2","versionType":"git"},{"lessThan":"92a8cb1806adefb263cf096eab6705705cf7eee1","status":"affected","version":"98d7ca374ba4b39e7535613d40e159f09ca14da2","versionType":"git"},{"lessThan":"65d114b5270b62aefb820ecd6c3b7caeea8f895d","status":"affected","version":"98d7ca374ba4b39e7535613d40e159f09ca14da2","versionType":"git"},{"lessThan":"af9e89d8dd39530c8bd14c33ddf6b502df1071b6","status":"affected","version":"98d7ca374ba4b39e7535613d40e159f09ca14da2","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["kernel/bpf/verifier.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.11"},{"lessThan":"6.11","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.75","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.14","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.75","versionStartIncluding":"6.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.14","versionStartIncluding":"6.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.4","versionStartIncluding":"6.11","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"6.11","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Preserve id of register in sync_linked_regs()\n\nsync_linked_regs() copies the id of known_reg to reg when propagating\nbounds of known_reg to reg using the off of known_reg, but when\nknown_reg was linked to reg like:\n\nknown_reg = reg         ; both known_reg and reg get same id\nknown_reg += 4          ; known_reg gets off = 4, and its id gets BPF_ADD_CONST\n\nnow when a call to sync_linked_regs() happens, let's say with the following:\n\nif known_reg >= 10 goto pc+2\n\nknown_reg's new bounds are propagated to reg but now reg gets\nBPF_ADD_CONST from the copy.\n\nThis means if another link to reg is created like:\n\nanother_reg = reg       ; another_reg should get the id of reg but\n                          assign_scalar_id_before_mov() sees\n                          BPF_ADD_CONST on reg and assigns a new id to it.\n\nAs reg has a new id now, known_reg's link to reg is broken. If we find\nnew bounds for known_reg, they will not be propagated to reg.\n\nThis can be seen in the selftest added in the next commit:\n\n0: (85) call bpf_get_prandom_u32#7    ; R0=scalar()\n1: (57) r0 &= 255                     ; R0=scalar(smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))\n2: (bf) r1 = r0                       ; R0=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff)) R1=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))\n3: (07) r1 += 4                       ; R1=scalar(id=1+4,smin=umin=smin32=umin32=4,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))\n4: (a5) if r1 < 0xa goto pc+4         ; R1=scalar(id=1+4,smin=umin=smin32=umin32=10,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))\n5: (bf) r2 = r0                       ; R0=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=255) R2=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=255)\n6: (a5) if r1 < 0xe goto pc+2         ; R1=scalar(id=1+4,smin=umin=smin32=umin32=14,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))\n7: (35) if r0 >= 0xa goto pc+1        ; R0=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=9,var_off=(0x0; 0xf))\n8: (37) r0 /= 0\ndiv by zero\n\nWhen 4 is verified, r1's bounds are propagated to r0 but r0 also gets\nBPF_ADD_CONST (bug).\nWhen 5 is verified, r0 gets a new id (2) and its link with r1 is broken.\n\nAfter 6 we know r1 has bounds [14, 259] and therefore r0 should have\nbounds [10, 255], therefore the branch at 7 is always taken. But because\nr0's id was changed to 2, r1's new bounds are not propagated to r0.\nThe verifier still thinks r0 has bounds [6, 255] before 7 and execution\ncan reach div by zero.\n\nFix this by preserving id in sync_linked_regs() like off and subreg_def."}],"providerMetadata":{"dateUpdated":"2026-05-27T12:17:51.127Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/58059335e46537de682db84984f7716c813208c4"},{"url":"https://git.kernel.org/stable/c/92a8cb1806adefb263cf096eab6705705cf7eee1"},{"url":"https://git.kernel.org/stable/c/65d114b5270b62aefb820ecd6c3b7caeea8f895d"},{"url":"https://git.kernel.org/stable/c/af9e89d8dd39530c8bd14c33ddf6b502df1071b6"}],"title":"bpf: Preserve id of register in sync_linked_regs()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-45933","datePublished":"2026-05-27T12:17:51.127Z","dateReserved":"2026-05-13T15:03:33.086Z","dateUpdated":"2026-05-27T12:17:51.127Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-27 14:17:09","lastModifiedDate":"2026-05-27 14:48:03","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"45933","Ordinal":"1","Title":"bpf: Preserve id of register in sync_linked_regs()","CVE":"CVE-2026-45933","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"45933","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Preserve id of register in sync_linked_regs()\n\nsync_linked_regs() copies the id of known_reg to reg when propagating\nbounds of known_reg to reg using the off of known_reg, but when\nknown_reg was linked to reg like:\n\nknown_reg = reg         ; both known_reg and reg get same id\nknown_reg += 4          ; known_reg gets off = 4, and its id gets BPF_ADD_CONST\n\nnow when a call to sync_linked_regs() happens, let's say with the following:\n\nif known_reg >= 10 goto pc+2\n\nknown_reg's new bounds are propagated to reg but now reg gets\nBPF_ADD_CONST from the copy.\n\nThis means if another link to reg is created like:\n\nanother_reg = reg       ; another_reg should get the id of reg but\n                          assign_scalar_id_before_mov() sees\n                          BPF_ADD_CONST on reg and assigns a new id to it.\n\nAs reg has a new id now, known_reg's link to reg is broken. If we find\nnew bounds for known_reg, they will not be propagated to reg.\n\nThis can be seen in the selftest added in the next commit:\n\n0: (85) call bpf_get_prandom_u32#7    ; R0=scalar()\n1: (57) r0 &= 255                     ; R0=scalar(smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))\n2: (bf) r1 = r0                       ; R0=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff)) R1=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))\n3: (07) r1 += 4                       ; R1=scalar(id=1+4,smin=umin=smin32=umin32=4,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))\n4: (a5) if r1 < 0xa goto pc+4         ; R1=scalar(id=1+4,smin=umin=smin32=umin32=10,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))\n5: (bf) r2 = r0                       ; R0=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=255) R2=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=255)\n6: (a5) if r1 < 0xe goto pc+2         ; R1=scalar(id=1+4,smin=umin=smin32=umin32=14,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))\n7: (35) if r0 >= 0xa goto pc+1        ; R0=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=9,var_off=(0x0; 0xf))\n8: (37) r0 /= 0\ndiv by zero\n\nWhen 4 is verified, r1's bounds are propagated to r0 but r0 also gets\nBPF_ADD_CONST (bug).\nWhen 5 is verified, r0 gets a new id (2) and its link with r1 is broken.\n\nAfter 6 we know r1 has bounds [14, 259] and therefore r0 should have\nbounds [10, 255], therefore the branch at 7 is always taken. But because\nr0's id was changed to 2, r1's new bounds are not propagated to r0.\nThe verifier still thinks r0 has bounds [6, 255] before 7 and execution\ncan reach div by zero.\n\nFix this by preserving id in sync_linked_regs() like off and subreg_def.","Type":"Description","Title":"bpf: Preserve id of register in sync_linked_regs()"}]}}}