CVE-2026-80843
Received Received - Intake

Memory Leak in Linux Kernel XFRM Subsystem

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: xfrm: fix xfrm_state_construct() auth-trunc leak attach_auth_trunc() can allocate x->aalg while leaving x->props.aalgo at zero when the selected auth algorithm has no sadb_alg_id. One real case is cmac(aes). xfrm_state_construct() then treats !x->props.aalgo as "no auth algorithm attached yet" and calls attach_auth(). That overwrites x->aalg and loses the first allocation. Any later failure or teardown only frees the replacement pointer. Check whether x->aalg is already attached instead of inferring that state from x->props.aalgo.

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Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-04
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
CVE-2026-80843
EUVD
EUVD-2026-71293

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

CWE
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a memory leak in the xfrm_state_construct() function. When an authentication algorithm without a sadb_alg_id is selected, like cmac(aes), the function attach_auth_trunc() allocates memory for x->aalg but leaves x->props.aalgo at zero. Later, attach_auth() overwrites x->aalg, causing the original allocation to be lost and leading to a memory leak during failure or teardown.

Detection Guidance

This vulnerability is specific to the Linux kernel's xfrm_state_construct() function and may not have direct detection commands. Monitor kernel logs for xfrm-related errors or crashes. Check for unexpected memory leaks in xfrm_state allocations using tools like slabtop or vmstat.

Impact Analysis

This vulnerability can cause memory leaks in the Linux kernel, potentially leading to resource exhaustion. It may affect systems using IPsec with authentication algorithms like cmac(aes), causing instability or crashes due to memory depletion.

Mitigation Strategies

Update your Linux kernel to the latest stable version that includes the fix for this vulnerability. If immediate patching is not possible, restrict network access to xfrm-related services or disable unused xfrm features to reduce attack surface.

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