bpf: Fix out-of-bounds dynptr write in bpf_crypto_crypt
Stanislav reported that in bpf_crypto_crypt() the destination dynptr's
size is not validated to be at least as large as the source dynptr's
size before calling into the crypto backend with 'len = src_len'. This
can result in an OOB write when the destination is smaller than the
source.
Concretely, in mentioned function, psrc and pdst are both linear
buffers fetched from each dynptr:
psrc = __bpf_dynptr_data(src, src_len);
[...]
pdst = __bpf_dynptr_data_rw(dst, dst_len);
[...]
err = decrypt ?
ctx->type->decrypt(ctx->tfm, psrc, pdst, src_len, piv) :
ctx->type->encrypt(ctx->tfm, psrc, pdst, src_len, piv);
The crypto backend expects pdst to be large enough with a src_len length
that can be written. Add an additional src_len > dst_len check and bail
out if it's the case. Note that these kfuncs are accessible under root
privileges only.
No advisories yet.
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Wed, 14 Jan 2026 18:15:00 +0000
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ssvc
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Fri, 12 Dec 2025 18:30:00 +0000
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| Weaknesses | CWE-787 | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* |
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| Metrics |
cvssV3_1
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cvssV3_1
|
Thu, 02 Oct 2025 12:15:00 +0000
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| References |
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| Metrics |
threat_severity
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cvssV3_1
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Thu, 02 Oct 2025 09:00:00 +0000
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|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
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| Vendors & Products |
Linux
Linux linux Kernel |
Wed, 01 Oct 2025 08:00:00 +0000
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| Description | In the Linux kernel, the following vulnerability has been resolved: bpf: Fix out-of-bounds dynptr write in bpf_crypto_crypt Stanislav reported that in bpf_crypto_crypt() the destination dynptr's size is not validated to be at least as large as the source dynptr's size before calling into the crypto backend with 'len = src_len'. This can result in an OOB write when the destination is smaller than the source. Concretely, in mentioned function, psrc and pdst are both linear buffers fetched from each dynptr: psrc = __bpf_dynptr_data(src, src_len); [...] pdst = __bpf_dynptr_data_rw(dst, dst_len); [...] err = decrypt ? ctx->type->decrypt(ctx->tfm, psrc, pdst, src_len, piv) : ctx->type->encrypt(ctx->tfm, psrc, pdst, src_len, piv); The crypto backend expects pdst to be large enough with a src_len length that can be written. Add an additional src_len > dst_len check and bail out if it's the case. Note that these kfuncs are accessible under root privileges only. | |
| Title | bpf: Fix out-of-bounds dynptr write in bpf_crypto_crypt | |
| References |
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Projects
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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-01-14T17:52:47.721Z
Reserved: 2025-04-16T07:20:57.147Z
Link: CVE-2025-39917
Updated: 2026-01-14T17:42:57.409Z
Status : Modified
Published: 2025-10-01T08:15:34.887
Modified: 2026-01-14T18:16:40.017
Link: CVE-2025-39917
OpenCVE Enrichment
Updated: 2025-10-02T08:40:06Z