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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-43492 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: lib/crypto: mpi: Fix integer underflow in mpi_read_raw_from_sgl() Yiming reports an integer underflow in mpi_read_raw_from_sgl() when subtracting "lzeros" from the unsigned "nbytes". For this to happen, the scatterlist "sgl" needs to occupy more bytes than the "nbytes" parameter and the first "nbytes + 1" bytes of the scatterlist must be zero. Under these conditions, the while loop iterating over the scatterlist will count more zeroes than "nbytes", subtract the number of zeroes from "nbytes" and cause the underflow. When commit 2d4d1eea540b ("lib/mpi: Add mpi sgl helpers") originally introduced the bug, it couldn't be triggered because all callers of mpi_read_raw_from_sgl() passed a scatterlist whose length was equal to "nbytes". However since commit 63ba4d67594a ("KEYS: asymmetric: Use new crypto interface without scatterlists"), the underflow can now actually be triggered. When invoking a KEYCTL_PKEY_ENCRYPT system call with a larger "out_len" than "in_len" and filling the "in" buffer with zeroes, crypto_akcipher_sync_prep() will create an all-zero scatterlist used for both the "src" and "dst" member of struct akcipher_request and thereby fulfil the conditions to trigger the bug: sys_keyctl() keyctl_pkey_e_d_s() asymmetric_key_eds_op() software_key_eds_op() crypto_akcipher_sync_encrypt() crypto_akcipher_sync_prep() crypto_akcipher_encrypt() rsa_enc() mpi_read_raw_from_sgl() To the user this will be visible as a DoS as the kernel spins forever, causing soft lockup splats as a side effect. Fix it.


Metrics

 
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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
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URL Source(s) Tag(s)
https://git.kernel.org/stable/c/26d3a97ad46c7a9226ec04d4bf35bd4998a97d16 kernel.org
https://git.kernel.org/stable/c/2aa77a18dc7f2670497fe3ee5acbeda0b57659e5 kernel.org
https://git.kernel.org/stable/c/30e513e755bb381afce6fb57cdc8694136193f22 kernel.org
https://git.kernel.org/stable/c/8637dfb4c1d8a7026ef681f2477c6de8b71c4003 kernel.org
https://git.kernel.org/stable/c/8c2f1288250a90a4b5cabed5d888d7e3aeed4035 kernel.org

Weakness Enumeration

CWE-ID CWE Name Source

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-43492
NVD Published Date:
05/19/2026
NVD Last Modified:
05/19/2026
Source:
kernel.org