CVE-2026-92485 (GCVE-0-2026-92485)
Vulnerability from cvelistv5
Published
2026-09-17 16:10
Modified
2026-10-30 12:35
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix WARNING in bpf_tracing_link_release
The trampoline could be corrupted by the blindly
'tr->flags = BPF_TRAMP_F_TAIL_CALL_CTX' in verifier.
1. A fexit attached to a tail_call_reachable prog. 'tr->flags' became
'BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_TAIL_CALL_CTX'. And, the
trampoline would poke the target prog's nop insn using jmp insn instead
of call insn.
2. Another fexit loaded with the same tail_call_reachable prog target.
'tr->flags' became 'BPF_TRAMP_F_TAIL_CALL_CTX'.
3. Close the first fexit link. Due to no BPF_TRAMP_F_CALL_ORIG in
'tr->flags', the trampoline will fail to restore the prog's nop insn
using call insn.
[ 3.410719] WARNING: kernel/bpf/syscall.c:3551 at bpf_tracing_link_release+0x53/0x60, CPU#1: test_progs/98
...
[ 3.428793] bpf_link_free+0x58/0x130
[ 3.429293] bpf_link_release+0x23/0x30
Fix the warning by updating 'tr->flags' with '|=' and lock.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 605c8d8f9966fcd2f0b858fabebe416fc83f2209 Version: 8f873cc3f67f2257493063e57d0caf07ef889ee9 Version: 2b5dcb31a19a2e0acd869b12c9db9b2d696ef544 Version: 2b5dcb31a19a2e0acd869b12c9db9b2d696ef544 Version: 2b5dcb31a19a2e0acd869b12c9db9b2d696ef544 Version: 2b5dcb31a19a2e0acd869b12c9db9b2d696ef544 Version: 028480eaf2a1401e914a1fa1a4a21d877cf0ae30 Version: 6.1.72 ≤ Version: 6.6.2 ≤ Version: 6.5.12 ≤ |
||
{
"containers": {
"cna": {
"affected": [
{
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"product": "Linux",
"programFiles": [
"include/linux/bpf.h",
"kernel/bpf/trampoline.c",
"kernel/bpf/verifier.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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{
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{
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]
},
{
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"programFiles": [
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"kernel/bpf/verifier.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": "6.1.*",
"status": "unaffected",
"version": "6.1.191",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.114",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.191",
"versionStartIncluding": "6.1.72",
"vulnerable": true
},
{
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{
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{
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{
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{
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.5.12",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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\u0027tr-\u003eflags = BPF_TRAMP_F_TAIL_CALL_CTX\u0027 in verifier.\n\n1. A fexit attached to a tail_call_reachable prog. \u0027tr-\u003eflags\u0027 became\n \u0027BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_TAIL_CALL_CTX\u0027. And, the\n trampoline would poke the target prog\u0027s nop insn using jmp insn instead\n of call insn.\n2. Another fexit loaded with the same tail_call_reachable prog target.\n \u0027tr-\u003eflags\u0027 became \u0027BPF_TRAMP_F_TAIL_CALL_CTX\u0027.\n3. Close the first fexit link. Due to no BPF_TRAMP_F_CALL_ORIG in\n \u0027tr-\u003eflags\u0027, the trampoline will fail to restore the prog\u0027s 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 \u0027tr-\u003eflags\u0027 with \u0027|=\u0027 and lock."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"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-\u003eflags), 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-\u003eflags = 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\u0027s 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\u0027s 5-byte slot as a JMP into the trampoline image that still calls fexit1-\u003ebpf_func, while bpf_link_free()\u2192bpf_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\u0027s 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": {
"dateUpdated": "2026-10-30T12:35:38.840Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"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"
}
],
"title": "bpf: Fix WARNING in bpf_tracing_link_release",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-92485",
"datePublished": "2026-09-17T16:10:00.999Z",
"dateReserved": "2026-09-16T12:21:13.870Z",
"dateUpdated": "2026-10-30T12:35:38.840Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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