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Linux Kernel CAAM CVE-2026-43044

| EUVDEUVD-2026-26643 HIGH
2026-05-01 Linux
Information Disclosure Linux Red Hat Suse
7.8
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SUSE
HIGH
qualitative
Red Hat
6.1 MEDIUM
qualitative

Primary rating from NVD.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

7
Analysis Generated
May 03, 2026 - 07:38 vuln.today
CVSS changed
May 03, 2026 - 07:22 NVD
7.8 (HIGH)
Patch released
May 03, 2026 - 07:16 nvd
Patch available
Patch available
May 01, 2026 - 16:33 EUVD
EUVD ID Assigned
May 01, 2026 - 15:00 euvd
EUVD-2026-26643
Analysis Generated
May 01, 2026 - 15:00 vuln.today
CVE Published
May 01, 2026 - 14:15 nvd
HIGH 7.8

DescriptionCVE.org

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

crypto: caam - fix DMA corruption on long hmac keys

When a key longer than block size is supplied, it is copied and then hashed into the real key. The memory allocated for the copy needs to be rounded to DMA cache alignment, as otherwise the hashed key may corrupt neighbouring memory.

The rounding was performed, but never actually used for the allocation. Fix this by replacing kmemdup with kmalloc for a larger buffer, followed by memcpy.

AnalysisAI

Memory corruption in the Linux kernel CAAM (Cryptographic Acceleration and Assurance Module) crypto driver allows local authenticated users to corrupt kernel memory and potentially escalate privileges. The vulnerability occurs when HMAC keys longer than the hash block size are processed - the driver allocates a DMA-aligned buffer size but fails to use it, causing the hashed key to overwrite adjacent memory. Vendor patches are available for stable kernel versions 6.6.134, 6.12.81, 6.18.22, 6.19.12, and 7.0. EPSS score of 0.02% (5th percentile) indicates very low observed exploitation probability, and no public exploit code or CISA KEV listing exists at time of analysis.

Technical ContextAI

This affects the Linux kernel's CAAM cryptographic hardware acceleration driver, specifically the HMAC key processing logic. HMAC operations require keys exactly matching the hash block size (e.g., 64 bytes for SHA-256). When users supply longer keys, the crypto subsystem must hash them down to size. The CAAM driver allocates a temporary buffer for this operation and correctly calculates DMA cache-aligned size to prevent cache line corruption, but then calls kmemdup() with the original unaligned size instead of using the calculated alignment. On architectures with DMA cache coherency requirements (common in ARM-based systems using CAAM hardware like NXP i.MX and Layerscape processors), this causes the hashed key write to corrupt adjacent kernel memory structures when cache lines are flushed. The vulnerability stems from a classic allocation-versus-usage size mismatch bug. The affected code path is in the kernel crypto API's CAAM backend, which provides hardware-accelerated cryptographic operations for embedded and networking devices.

RemediationAI

Upgrade to patched Linux kernel versions: 6.6.134 or later for 6.6.x series, 6.12.81 or later for 6.12.x series, 6.18.22 or later for 6.18.x series, 6.19.12 or later for 6.19.x series, or 7.0 or later for mainline. Upstream fix commits are available at https://git.kernel.org/stable/c/a7ecf06d3ee06e9b3322e1e7b003ea5c6f6e135a (mainline) and branch-specific commits c0c133e0225d, 68feed135a0c, f2af8be110bd, and 5ddfdcbe10dc. Organizations unable to patch immediately can implement compensating controls: restrict local user access to cryptographic APIs by enforcing MAC policies (SELinux/AppArmor) that deny unprivileged access to /dev/crypto or AF_ALG sockets, though this may break legitimate cryptographic applications. Alternatively, disable the CAAM driver module (caam, caam_jr, caamhash) and fall back to software crypto implementations, accepting the performance penalty of losing hardware acceleration. On systems where HMAC is not used or keys never exceed block size, exploitation risk is theoretical but patching remains recommended as defense in depth.

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Vendor StatusVendor

SUSE

Severity: High
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Fixed
SUSE Linux Enterprise Desktop 15 SP7 Fixed
SUSE Linux Enterprise High Availability Extension 15 SP7 Fixed
SUSE Linux Enterprise High Availability Extension 15 SP7 Fixed
SUSE Linux Enterprise High Performance Computing 15 SP7 Fixed

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CVE-2026-43044 vulnerability details – vuln.today
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