VulnerabilityPublished 19 May 2026Updated 10 Nov 2026

CVE-2026-43492: Linux kernel · lib/crypto: mpi: Fix integer underflow in mpi_read_raw_from_sgl()

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in a1793a48881ec8d26e9c79b0ee65753f1c6846a4 : patch Linux kernel soon.

Data as of 10 Nov 2026, 13:05 UTC

Severity

High

Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Patch: Available – fixed in a1793a48881ec8d26e9c79b0ee65753f1c6846a4, 8637dfb4c1d8a7026ef681f2477c6de8b71c4003, 30e513e755bb381afce6fb57cdc8694136193f22 +5

Exploitation evidence

Disclosed: evidence found.
CVE published 19 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 2d4d1eea540b27c72488fd1914674c42473d53df, < a1793a48881ec8d26e9c79b0ee65753f1c6846a4	Fixed in a1793a48881ec8d26e9c79b0ee65753f1c6846a4
LinuxLinux	Affected ≥ 2d4d1eea540b27c72488fd1914674c42473d53df, < 8637dfb4c1d8a7026ef681f2477c6de8b71c4003	Fixed in 8637dfb4c1d8a7026ef681f2477c6de8b71c4003
LinuxLinux	Affected ≥ 2d4d1eea540b27c72488fd1914674c42473d53df, < 30e513e755bb381afce6fb57cdc8694136193f22	Fixed in 30e513e755bb381afce6fb57cdc8694136193f22
LinuxLinux	Affected ≥ 2d4d1eea540b27c72488fd1914674c42473d53df, < 26d3a97ad46c7a9226ec04d4bf35bd4998a97d16	Fixed in 26d3a97ad46c7a9226ec04d4bf35bd4998a97d16
LinuxLinux	Affected ≥ 2d4d1eea540b27c72488fd1914674c42473d53df, < 8c2f1288250a90a4b5cabed5d888d7e3aeed4035	Fixed in 8c2f1288250a90a4b5cabed5d888d7e3aeed4035
LinuxLinux	Affected ≥ 2d4d1eea540b27c72488fd1914674c42473d53df, < 6d63615c796c085b4984e3031b9fa77fffb47360	Fixed in 6d63615c796c085b4984e3031b9fa77fffb47360

AI-suggested

The vulnerability has been fixed in multiple Linux kernel commits. Users and administrators should apply the official Linux kernel updates containing these fixes. No additional mitigation is required once the system is updated.

Description

An integer underflow vulnerability in the Linux kernel's mpi_read_raw_from_sgl() function can cause a denial of service (DoS) by making the kernel spin indefinitely, leading to soft lockup crashes. The flaw arises when a scatterlist with more bytes than the specified nbytes parameter is processed, and the initial bytes are all zero, causing an underflow in the subtraction operation. This issue was introduced by a commit that added mpi sgl helpers and became exploitable after a later commit changed how scatterlists are used in cryptographic operations. The vulnerability is fixed in several Linux kernel commits.

Impact

The vulnerability causes a denial of service by making the Linux kernel enter an infinite loop, leading to soft lockup crashes. This can be triggered by a user invoking the KEYCTL_PKEY_ENCRYPT syscall with crafted parameters, causing the kernel to spin indefinitely. There is no indication of privilege escalation or data corruption beyond the DoS impact.

Summary

CVE-2026-43492 is an integer underflow vulnerability in the Linux kernel's lib/crypto mpi subsystem, specifically in the mpi_read_raw_from_sgl() function. The bug occurs when the function subtracts the count of leading zero bytes (lzeros) from an unsigned nbytes parameter, under conditions where the scatterlist length exceeds nbytes and the first nbytes+1 bytes are zero. This leads to an underflow causing an infinite loop, resulting in a kernel soft lockup (DoS). The vulnerability became exploitable after a commit changed the crypto interface to use scatterlists differently, allowing the conditions to be met during a KEYCTL_PKEY_ENCRYPT syscall with crafted input buffers. The issue is fixed in multiple Linux kernel commits referenced by their hashes.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Nov 2026, 13:05 UTC

Technical details

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