CVE-2026-74438 - Vulnerability Details

- crypto: sun4i-ss - Remove insecure and unused rng_alg

Description

In the Linux kernel, the following vulnerability has been resolved:

crypto: sun4i-ss - Remove insecure and unused rng_alg

Remove sun4i_ss_rng, as it is insecure and unused:

- It has multiple vulnerabilities. sun4i_ss_prng_seed() is missing
locking and has a buffer overflow. sun4i_ss_prng_generate() fails to
fill the entire buffer with cryptographic random bytes, because it
rounds the destination length down and also doesn't actually wait for
the hardware to be ready before pulling bytes from it.

- No user of this code is known. It's usable only theoretically via the
"rng" algorithm type of AF_ALG. But userspace actually just uses the
actual Linux RNG (/dev/random etc) instead. And rng_algs don't
contribute entropy to the actual Linux RNG either. (This may have
been confused with hwrng, which does contribute entropy.)

The sun4i_ss_prng_seed() buffer overflow was reported by Tianchu Chen
and discovered by Atuin - Automated Vulnerability Discovery Engine

There's no point in fixing all these vulnerabilities individually when
this is unused code, so let's just remove it.

Published: 2026-08-15

Score: 7.8 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

The Linux kernel’s sun4i-ss RNG implementation contained a seeding function that lacked proper locking and suffered a buffer overflow, and a generation function that truncated its output and did not synchronize with the underlying hardware. These flaws could corrupt memory or cause the kernel to deliver incomplete entropy, creating the possibility of denial of service or arbitrary code execution if the code were exercised.

Affected Systems

The vulnerable code resides in the Linux kernel and affects any kernel version that includes the sun4i_ss_rng implementation before it was removed. The code is only reachable via the AF_ALG "rng" interface and has not been used by normal userspace components.

Risk and Exploitability

The CVSS score is 7.8 and the EPSS score is below 1 %. The vulnerability is not listed in CISA KEV. Attackers would need to invoke the removed RNG algorithm through AF_ALG; however, no real‑world usage of the code has been documented, so the practical risk is low but remediation is recommended.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`b8ae5c7387ad075ee61e8c8774ce2bca46bc9236`	affected	< 2eafecaba1b46bb9774eaf3556619fd5b6a17c1c
`b8ae5c7387ad075ee61e8c8774ce2bca46bc9236`	affected	< ee2458f8188732aa53a5d42f56e87bfad288b44e
`b8ae5c7387ad075ee61e8c8774ce2bca46bc9236`	affected	< 306ded31bfa00a69d25823a60d7c797170bfb4f8
`b8ae5c7387ad075ee61e8c8774ce2bca46bc9236`	affected	< e4b7b9819811c4c51064c3d3d3c02f0be7491707
`b8ae5c7387ad075ee61e8c8774ce2bca46bc9236`	affected	< c401492e01c7bfd38cf14c94d85c7efafe7d1a25
`b8ae5c7387ad075ee61e8c8774ce2bca46bc9236`	affected	< 9c8086d9511189c34dfa3f9e3a03f2bee12f56a5
`b8ae5c7387ad075ee61e8c8774ce2bca46bc9236`	affected	< b2c41fa9dd8fc740c489e060b199165771f268d1

Linux

affected

Version	Status	Constraints
`4.14`	affected	—
`0`	unaffected	< 4.14
`5.15.212`	unaffected	≤ 5.15.*
`6.1.178`	unaffected	≤ 6.1.*
`6.6.145`	unaffected	≤ 6.6.*
`6.12.97`	unaffected	≤ 6.12.*
`6.18.40`	unaffected	≤ 6.18.*
`7.1.5`	unaffected	≤ 7.1.*
`7.2`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[b8ae5c7387ad075ee61e8c8774ce2bca46bc9236,2eafecaba1b46bb9774eaf3556619fd5b6a17c1c)`	affected	code_commit	—
`[b8ae5c7387ad075ee61e8c8774ce2bca46bc9236,ee2458f8188732aa53a5d42f56e87bfad288b44e)`	affected	code_commit	—
`[b8ae5c7387ad075ee61e8c8774ce2bca46bc9236,306ded31bfa00a69d25823a60d7c797170bfb4f8)`	affected	code_commit	—
`[b8ae5c7387ad075ee61e8c8774ce2bca46bc9236,e4b7b9819811c4c51064c3d3d3c02f0be7491707)`	affected	code_commit	—
`[b8ae5c7387ad075ee61e8c8774ce2bca46bc9236,c401492e01c7bfd38cf14c94d85c7efafe7d1a25)`	affected	code_commit	—
`[b8ae5c7387ad075ee61e8c8774ce2bca46bc9236,9c8086d9511189c34dfa3f9e3a03f2bee12f56a5)`	affected	code_commit	—
`[b8ae5c7387ad075ee61e8c8774ce2bca46bc9236,b2c41fa9dd8fc740c489e060b199165771f268d1)`	affected	code_commit	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`4.14`	affected	semver	—
`[0,4.14)`	unaffected	semver	—
`[5.15.212,5.16.0)`	unaffected	semver	—
`[6.1.178,6.2.0)`	unaffected	semver	—
`[6.6.145,6.7.0)`	unaffected	semver	—
`[6.12.97,6.13.0)`	unaffected	semver	—
`[7.1.5,7.2.0)`	unaffected	semver	—
`[7.2-rc1,*]`	unaffected	generic	—

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Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

Apply a Linux kernel update that includes the commit removing the sun4i_ss_rng implementation.
If no update is available, rebuild the kernel with the sun4i-ss RNG support disabled or the source file excluded.
Verify that no system components or user applications use the sun4i_ss_rng algorithm via AF_ALG or a custom RNG interface.

Generated by OpenCVE AI on August 21, 2026 at 23:30 UTC.

Tracking

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Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00133.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/2eafecaba1b46bb9774eaf3556619fd5b6a17c1c
https://git.kernel.org/stable/c/306ded31bfa00a69d25823a60d7c797170bfb4f8
https://git.kernel.org/stable/c/9c8086d9511189c34dfa3f9e3a03f2bee12f56a5
https://git.kernel.org/stable/c/b2c41fa9dd8fc740c489e060b199165771f268d1
https://git.kernel.org/stable/c/c401492e01c7bfd38cf14c94d85c7efafe7d1a25
https://git.kernel.org/stable/c/e4b7b9819811c4c51064c3d3d3c02f0be7491707
https://git.kernel.org/stable/c/ee2458f8188732aa53a5d42f56e87bfad288b44e
https://lore.kernel.org/linux-cve-announce/2026081516-CVE-2026-74438-d66c@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2026-74438
https://www.cve.org/CVERecord?id=CVE-2026-74438

History

Fri, 21 Aug 2026 22:30:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-119 CWE-362

Fri, 21 Aug 2026 12:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-120
References		https://lore.kernel.org/linux-cve-announce/2026081516-CVE-2026-74438-d66c@gregkh/T https://nvd.nist.gov/vuln/detail/CVE-2026-74438 https://www.cve.org/CVERecord?id=CVE-2026-74438
Metrics	threat_severity `None`	threat_severity `Moderate`

Mon, 17 Aug 2026 14:45:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-119 CWE-362

Mon, 17 Aug 2026 12:15:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-119 CWE-362

Mon, 17 Aug 2026 06:00:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}`

Sat, 15 Aug 2026 14:00:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-119 CWE-362

Sat, 15 Aug 2026 06:15:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: crypto: sun4i-ss - Remove insecure and unused rng_alg Remove sun4i_ss_rng, as it is insecure and unused: - It has multiple vulnerabilities. sun4i_ss_prng_seed() is missing locking and has a buffer overflow. sun4i_ss_prng_generate() fails to fill the entire buffer with cryptographic random bytes, because it rounds the destination length down and also doesn't actually wait for the hardware to be ready before pulling bytes from it. - No user of this code is known. It's usable only theoretically via the "rng" algorithm type of AF_ALG. But userspace actually just uses the actual Linux RNG (/dev/random etc) instead. And rng_algs don't contribute entropy to the actual Linux RNG either. (This may have been confused with hwrng, which does contribute entropy.) The sun4i_ss_prng_seed() buffer overflow was reported by Tianchu Chen and discovered by Atuin - Automated Vulnerability Discovery Engine There's no point in fixing all these vulnerabilities individually when this is unused code, so let's just remove it.
Title		crypto: sun4i-ss - Remove insecure and unused rng_alg
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/2eafecaba1b46bb9774eaf3556619fd5b6a17c1c https://git.kernel.org/stable/c/306ded31bfa00a69d25823a60d7c797170bfb4f8 https://git.kernel.org/stable/c/9c8086d9511189c34dfa3f9e3a03f2bee12f56a5 https://git.kernel.org/stable/c/b2c41fa9dd8fc740c489e060b199165771f268d1 https://git.kernel.org/stable/c/c401492e01c7bfd38cf14c94d85c7efafe7d1a25 https://git.kernel.org/stable/c/e4b7b9819811c4c51064c3d3d3c02f0be7491707 https://git.kernel.org/stable/c/ee2458f8188732aa53a5d42f56e87bfad288b44e

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-08-15T05:59:36.044Z

Updated: 2026-08-17T05:47:12.124Z

Reserved: 2026-08-15T05:44:03.897Z

Link: CVE-2026-74438

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-08-15T06:22:45.903

Modified: 2026-08-17T06:19:39.477

Link: CVE-2026-74438

Redhat

Severity : Moderate

Publid Date: 2026-08-15T00:00:00Z

Links: CVE-2026-74438 - Bugzilla

OpenCVE Enrichment

Updated: 2026-08-21T23:30:17Z

Weaknesses

CWE-120
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Subscriptions

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