CVE-2026-23417 (GCVE-0-2026-23417)
Vulnerability from cvelistv5
Published
2026-04-02 11:40
Modified
2026-04-13 06:07
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix constant blinding for PROBE_MEM32 stores
BPF_ST | BPF_PROBE_MEM32 immediate stores are not handled by
bpf_jit_blind_insn(), allowing user-controlled 32-bit immediates to
survive unblinded into JIT-compiled native code when bpf_jit_harden >= 1.
The root cause is that convert_ctx_accesses() rewrites BPF_ST|BPF_MEM
to BPF_ST|BPF_PROBE_MEM32 for arena pointer stores during verification,
before bpf_jit_blind_constants() runs during JIT compilation. The
blinding switch only matches BPF_ST|BPF_MEM (mode 0x60), not
BPF_ST|BPF_PROBE_MEM32 (mode 0xa0). The instruction falls through
unblinded.
Add BPF_ST|BPF_PROBE_MEM32 cases to bpf_jit_blind_insn() alongside the
existing BPF_ST|BPF_MEM cases. The blinding transformation is identical:
load the blinded immediate into BPF_REG_AX via mov+xor, then convert
the immediate store to a register store (BPF_STX).
The rewritten STX instruction must preserve the BPF_PROBE_MEM32 mode so
the architecture JIT emits the correct arena addressing (R12-based on
x86-64). Cannot use the BPF_STX_MEM() macro here because it hardcodes
BPF_MEM mode; construct the instruction directly instead.
References
| URL | Tags | |
|---|---|---|
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/bpf/core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
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"versionType": "git"
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"status": "affected",
"version": "6082b6c328b5486da2b356eae94b8b83c98b5565",
"versionType": "git"
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{
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"versionType": "git"
},
{
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"status": "affected",
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"programFiles": [
"kernel/bpf/core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.9"
},
{
"lessThan": "6.9",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.80",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.21",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.11",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"nodes": [
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"versionStartIncluding": "6.9",
"vulnerable": true
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{
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{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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{
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"negate": false,
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix constant blinding for PROBE_MEM32 stores\n\nBPF_ST | BPF_PROBE_MEM32 immediate stores are not handled by\nbpf_jit_blind_insn(), allowing user-controlled 32-bit immediates to\nsurvive unblinded into JIT-compiled native code when bpf_jit_harden \u003e= 1.\n\nThe root cause is that convert_ctx_accesses() rewrites BPF_ST|BPF_MEM\nto BPF_ST|BPF_PROBE_MEM32 for arena pointer stores during verification,\nbefore bpf_jit_blind_constants() runs during JIT compilation. The\nblinding switch only matches BPF_ST|BPF_MEM (mode 0x60), not\nBPF_ST|BPF_PROBE_MEM32 (mode 0xa0). The instruction falls through\nunblinded.\n\nAdd BPF_ST|BPF_PROBE_MEM32 cases to bpf_jit_blind_insn() alongside the\nexisting BPF_ST|BPF_MEM cases. The blinding transformation is identical:\nload the blinded immediate into BPF_REG_AX via mov+xor, then convert\nthe immediate store to a register store (BPF_STX).\n\nThe rewritten STX instruction must preserve the BPF_PROBE_MEM32 mode so\nthe architecture JIT emits the correct arena addressing (R12-based on\nx86-64). Cannot use the BPF_STX_MEM() macro here because it hardcodes\nBPF_MEM mode; construct the instruction directly instead."
}
],
"providerMetadata": {
"dateUpdated": "2026-04-13T06:07:02.830Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/56af722756ed82fee2ae5d5b4d04743407506195"
},
{
"url": "https://git.kernel.org/stable/c/ccbf29b28b5554f9d65b2fb53b994673ad58b3bf"
},
{
"url": "https://git.kernel.org/stable/c/de641ea08f8fff6906e169d2576c2ac54e562fbb"
},
{
"url": "https://git.kernel.org/stable/c/2321a9596d2260310267622e0ad8fbfa6f95378f"
}
],
"title": "bpf: Fix constant blinding for PROBE_MEM32 stores",
"x_generator": {
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}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-23417",
"datePublished": "2026-04-02T11:40:57.837Z",
"dateReserved": "2026-01-13T15:37:46.014Z",
"dateUpdated": "2026-04-13T06:07:02.830Z",
"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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