bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing
In the Linux kernel, the following vulnerability has been resolved: bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing struct bpf_plt contains a u64 target field. Currently, the BPF JIT allocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT buffer. Because the base address of the JIT buffer can be 4-byte aligned (e.g., ending in 0x4 or 0xc), the relative padding logic in build_plt() fails to ensure that target lands on an 8-byte boundary. This leads to two issues: 1. UBSAN reports misaligned-access warnings when dereferencing the structure. 2. More critically, target is updated concurrently via WRITE_ONCE() in bpf_arch_text_poke() while the JIT'd code executes ldr. On arm64, 64-bit loads/stores are only guaranteed to be single-copy atomic if they are 64-bit aligned. A misaligned target risks a torn read, causing the JIT to jump to a corrupted address. Fix this by increasing the allocation alignment requirement to 8 bytes (sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of the JIT buffer to an 8-byte boundary, allowing the relative padding math in build_plt() to correctly align the target field.
CVE-2026-23383
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-23383
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "b2ad54e1533e91449cb2a371e034942bd7882b58",
"lessThan": "f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d",
"versionType": "git"
},
{
"status": "affected",
"version": "b2ad54e1533e91449cb2a371e034942bd7882b58",
"lessThan": "80ad264da02cc4aee718e799c2b79f0f834673dc",
"versionType": "git"
},
{
"status": "affected",
"version": "b2ad54e1533e91449cb2a371e034942bd7882b58",
"lessThan": "519b1ad91de5bf7a496f2b858e9212db6328e1de",
"versionType": "git"
},
{
"status": "affected",
"version": "b2ad54e1533e91449cb2a371e034942bd7882b58",
"lessThan": "66959ed481a474eaae278c7f6860a2a9b188a4d6",
"versionType": "git"
},
{
"status": "affected",
"version": "b2ad54e1533e91449cb2a371e034942bd7882b58",
"lessThan": "ef06fd16d48704eac868441d98d4ef083d8f3d07",
"versionType": "git"
}
],
"programFiles": [
"arch/arm64/net/bpf_jit_comp.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.0"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.77",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.17",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.7",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"arch/arm64/net/bpf_jit_comp.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-23383
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #46122 · Revision 1
- Added to Heist Feed
- Publisher date