{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-92485", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-16T12:21:13.870Z", "datePublished": "2026-09-17T16:10:00.999Z", "dateUpdated": "2026-10-21T12:51:42.393Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:51:42.393Z" }, "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." } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "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" ], "versions": [ { "version": "8f873cc3f67f2257493063e57d0caf07ef889ee9", "lessThan": "a5c6316052f0ff1467221ecf2996cbab0a496b1e", "status": "affected", "versionType": "git" }, { "version": "2b5dcb31a19a2e0acd869b12c9db9b2d696ef544", "lessThan": "d02035c5eb4955616efc5c6dbe3d98f19d798cb2", "status": "affected", "versionType": "git" }, { "version": "2b5dcb31a19a2e0acd869b12c9db9b2d696ef544", "lessThan": "094f0a895cf97a993d06d5dc4c12e7cb7da845a5", "status": "affected", "versionType": "git" }, { "version": "2b5dcb31a19a2e0acd869b12c9db9b2d696ef544", "lessThan": "48a0209d8da0d90a7b0a0db19d1ff88027b13781", "status": "affected", "versionType": "git" }, { "version": "2b5dcb31a19a2e0acd869b12c9db9b2d696ef544", "lessThan": "61aaa8782bec59ecffd22e030f54ef9351bcabf9", "status": "affected", "versionType": "git" }, { "version": "605c8d8f9966fcd2f0b858fabebe416fc83f2209", "status": "affected", "versionType": "git" }, { "version": "028480eaf2a1401e914a1fa1a4a21d877cf0ae30", "status": "affected", "versionType": "git" }, { "version": "6.6.2", "lessThan": "6.6.160", "status": "affected", "versionType": "semver" }, { "version": "6.1.72", "lessThan": "6.2", "status": "affected", "versionType": "semver" }, { "version": "6.5.12", "lessThan": "6.6", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "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" ], "versions": [ { "version": "6.7", "status": "affected" }, { "version": "0", "lessThan": "6.7", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.114", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.6", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "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": "6.1.72" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5.12" } ] } ] } ], "references": [ { "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" } ], "title": "bpf: Fix WARNING in bpf_tracing_link_release", "x_generator": { "engine": "bippy-1.2.0" } } } }