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Advisory details: ubuntu_osv / UBUNTU-CVE-2025-39917
Advisory ID ubuntu_osv/UBUNTU-CVE-2025-39917
Aliases CVE-2025-39917
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 7.0
Risk 3.5
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (0)
There are no known CWE.
System Score Found at
cvssv3.1 7.8 https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-39917.json
ubuntu-priority low https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-39917.json
Reference id Reference type URL
https://git.kernel.org/linus/f9bb6ffa7f5ad0f8ee0f53fc4a10655872ee4a14
https://ubuntu.com/security/CVE-2025-39917
https://www.cve.org/CVERecord?id=CVE-2025-39917
0126358df12d6f476f79251d9c398ac5c1b3062d Other https://git.kernel.org/stable/c/0126358df12d6f476f79251d9c398ac5c1b3062d
c4be24ef0510c146dca4671effb127e97631534b Other https://git.kernel.org/stable/c/c4be24ef0510c146dca4671effb127e97631534b
f9bb6ffa7f5ad0f8ee0f53fc4a10655872ee4a14 Other https://git.kernel.org/stable/c/f9bb6ffa7f5ad0f8ee0f53fc4a10655872ee4a14
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Found at https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-39917.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

There are no SSVC decisions available.