{"id":"CVE-2026-92485","state":"PUBLISHED","title":"bpf: Fix WARNING in bpf_tracing_link_release","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix WARNING in bpf_tracing_link_release\n\nThe trampoline could be corrupted by the blindly\n'tr->flags = BPF_TRAMP_F_TAIL_CALL_CTX' in verifier.\n\n1. A fexit attached to a tail_call_reachable prog. 'tr->flags' became\n   'BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_TAIL_CALL_CTX'. And, the\n   trampoline would poke the target prog's nop insn using jmp insn instead\n   of call insn.\n2. Another fexit loaded with the same tail_call_reachable prog target.\n   'tr->flags' became 'BPF_TRAMP_F_TAIL_CALL_CTX'.\n3. Close the first fexit link. Due to no BPF_TRAMP_F_CALL_ORIG in\n   'tr->flags', the trampoline will fail to restore the prog's nop insn\n   using call insn.\n\n[    3.410719] WARNING: kernel/bpf/syscall.c:3551 at bpf_tracing_link_release+0x53/0x60, CPU#1: test_progs/98\n...\n[    3.428793]  bpf_link_free+0x58/0x130\n[    3.429293]  bpf_link_release+0x23/0x30\n\nFix the warning by updating 'tr->flags' with '|=' and lock.","publishedAt":"2026-09-17T16:10:00.999Z","updatedAt":"2026-10-30T12:35:38.840Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"605c8d8f9966fcd2f0b858fabebe416fc83f2209","status":"affected","lessThan":"1757598b3804f7cb35b5b5e02558f6d8b9c2f254","versionType":"git"},{"version":"8f873cc3f67f2257493063e57d0caf07ef889ee9","status":"affected","lessThan":"a5c6316052f0ff1467221ecf2996cbab0a496b1e","versionType":"git"},{"version":"2b5dcb31a19a2e0acd869b12c9db9b2d696ef544","status":"affected","lessThan":"d02035c5eb4955616efc5c6dbe3d98f19d798cb2","versionType":"git"},{"version":"2b5dcb31a19a2e0acd869b12c9db9b2d696ef544","status":"affected","lessThan":"094f0a895cf97a993d06d5dc4c12e7cb7da845a5","versionType":"git"},{"version":"2b5dcb31a19a2e0acd869b12c9db9b2d696ef544","status":"affected","lessThan":"48a0209d8da0d90a7b0a0db19d1ff88027b13781","versionType":"git"},{"version":"2b5dcb31a19a2e0acd869b12c9db9b2d696ef544","status":"affected","lessThan":"61aaa8782bec59ecffd22e030f54ef9351bcabf9","versionType":"git"},{"version":"028480eaf2a1401e914a1fa1a4a21d877cf0ae30","status":"affected","versionType":"git"},{"version":"6.1.72","status":"affected","lessThan":"6.1.191","versionType":"semver"},{"version":"6.6.2","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.5.12","status":"affected","lessThan":"6.6","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/bpf.h","kernel/bpf/trampoline.c","kernel/bpf/verifier.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.7","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/bpf.h","kernel/bpf/trampoline.c","kernel/bpf/verifier.c"]}],"references":["https://git.kernel.org/stable/c/1757598b3804f7cb35b5b5e02558f6d8b9c2f254","https://git.kernel.org/stable/c/a5c6316052f0ff1467221ecf2996cbab0a496b1e","https://git.kernel.org/stable/c/d02035c5eb4955616efc5c6dbe3d98f19d798cb2","https://git.kernel.org/stable/c/094f0a895cf97a993d06d5dc4c12e7cb7da845a5","https://git.kernel.org/stable/c/48a0209d8da0d90a7b0a0db19d1ff88027b13781","https://git.kernel.org/stable/c/61aaa8782bec59ecffd22e030f54ef9351bcabf9"],"weaknesses":[],"ingestedAt":"2026-10-30T12:54:04.478Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/92xxx/CVE-2026-92485.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-92485","state":"PUBLISHED","datePublished":"2026-09-17T16:10:00.999Z","dateUpdated":"2026-10-30T12:35:38.840Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-16T12:21:13.870Z"},"containers":{"cna":{"title":"bpf: Fix WARNING in bpf_tracing_link_release","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix WARNING in bpf_tracing_link_release\n\nThe trampoline could be corrupted by the blindly\n'tr->flags = BPF_TRAMP_F_TAIL_CALL_CTX' in verifier.\n\n1. A fexit attached to a tail_call_reachable prog. 'tr->flags' became\n   'BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_TAIL_CALL_CTX'. And, the\n   trampoline would poke the target prog's nop insn using jmp insn instead\n   of call insn.\n2. Another fexit loaded with the same tail_call_reachable prog target.\n   'tr->flags' became 'BPF_TRAMP_F_TAIL_CALL_CTX'.\n3. Close the first fexit link. Due to no BPF_TRAMP_F_CALL_ORIG in\n   'tr->flags', the trampoline will fail to restore the prog's nop insn\n   using call insn.\n\n[    3.410719] WARNING: kernel/bpf/syscall.c:3551 at bpf_tracing_link_release+0x53/0x60, CPU#1: test_progs/98\n...\n[    3.428793]  bpf_link_free+0x58/0x130\n[    3.429293]  bpf_link_release+0x23/0x30\n\nFix the warning by updating 'tr->flags' with '|=' and lock."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"605c8d8f9966fcd2f0b858fabebe416fc83f2209","status":"affected","lessThan":"1757598b3804f7cb35b5b5e02558f6d8b9c2f254","versionType":"git"},{"version":"8f873cc3f67f2257493063e57d0caf07ef889ee9","status":"affected","lessThan":"a5c6316052f0ff1467221ecf2996cbab0a496b1e","versionType":"git"},{"version":"2b5dcb31a19a2e0acd869b12c9db9b2d696ef544","status":"affected","lessThan":"d02035c5eb4955616efc5c6dbe3d98f19d798cb2","versionType":"git"},{"version":"2b5dcb31a19a2e0acd869b12c9db9b2d696ef544","status":"affected","lessThan":"094f0a895cf97a993d06d5dc4c12e7cb7da845a5","versionType":"git"},{"version":"2b5dcb31a19a2e0acd869b12c9db9b2d696ef544","status":"affected","lessThan":"48a0209d8da0d90a7b0a0db19d1ff88027b13781","versionType":"git"},{"version":"2b5dcb31a19a2e0acd869b12c9db9b2d696ef544","status":"affected","lessThan":"61aaa8782bec59ecffd22e030f54ef9351bcabf9","versionType":"git"},{"version":"028480eaf2a1401e914a1fa1a4a21d877cf0ae30","status":"affected","versionType":"git"},{"version":"6.1.72","status":"affected","lessThan":"6.1.191","versionType":"semver"},{"version":"6.6.2","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.5.12","status":"affected","lessThan":"6.6","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/bpf.h","kernel/bpf/trampoline.c","kernel/bpf/verifier.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.7","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/bpf.h","kernel/bpf/trampoline.c","kernel/bpf/verifier.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/1757598b3804f7cb35b5b5e02558f6d8b9c2f254"},{"url":"https://git.kernel.org/stable/c/a5c6316052f0ff1467221ecf2996cbab0a496b1e"},{"url":"https://git.kernel.org/stable/c/d02035c5eb4955616efc5c6dbe3d98f19d798cb2"},{"url":"https://git.kernel.org/stable/c/094f0a895cf97a993d06d5dc4c12e7cb7da845a5"},{"url":"https://git.kernel.org/stable/c/48a0209d8da0d90a7b0a0db19d1ff88027b13781"},{"url":"https://git.kernel.org/stable/c/61aaa8782bec59ecffd22e030f54ef9351bcabf9"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The trigger is local bpf() only: BPF_PROG_LOAD of a tail_call_reachable target plus two BPF_TRACE_FEXIT programs (check_attach_btf_id overwrites tr->flags), BPF_LINK_CREATE via bpf_tracing_prog_attach, then close() of the first link into bpf_tracing_link_release. No remote protocol carries the malformed state.\nAC:L - After the first fexit attach, bpf_trampoline_update sets BPF_TRAMP_F_CALL_ORIG and bpf_arch_text_poke installs a JMP (bpf_trampoline_use_jmp). A second BPF_PROG_LOAD then does tr->flags = BPF_TRAMP_F_TAIL_CALL_CTX in check_attach_btf_id; closing the first link hits the JMP-vs-CALL mismatch. The attacker owns both loads and the close; CONFIG_DYNAMIC_FTRACE_WITH_JMP is def_bool y on x86_64.\nPR:L - bpf_prog_load() of BPF_PROG_TYPE_TRACING/BPF_TRACE_FEXIT requires CAP_BPF and, via is_perfmon_prog_type(), CAP_PERFMON; bpf_token_capable() with a delegated BPF token grants those into a non-init user namespace, so this is not init-namespace root.\nUI:N - The attacker loads both fexit programs, attaches the first with BPF_LINK_CREATE/bpf_tracing_prog_attach, and closes that link fd themselves; no victim mount, open, or other action is required.\nS:U - The leftover JMP in the target program and the use-after-free of fexit1's JIT image stay inside host kernel BPF trampoline code; they do not cross a VM, IOMMU, or sandbox boundary.\nC:H - Failed bpf_trampoline_unlink_prog() leaves the target's 5-byte slot as a JMP into the trampoline image that still calls fexit1->bpf_func, while bpf_link_free()→bpf_link_dealloc() immediately bpf_prog_put()s fexit1 (no dealloc_deferred). After bpf_jit_free(), later target invocations read that freed executable image.\nI:H - The same dangling trampoline CALL into fexit1's freed JIT pages is an executable use-after-free; the attacker controls the fexit program and can spray replacement JIT text at that address, hijacking kernel control flow when the target program runs.\nA:H - bpf_tracing_link_release() WARN_ON_ONCE()s the failed bpf_trampoline_unlink_prog() after bpf_arch_text_poke() rejects the JMP-vs-CALL restore. Running the target afterward jumps to the trampoline and calls the freed fexit JIT, causing a kernel paging fault/oops."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:35:38.840Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.72","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.2","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5.12"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}