Linux Kernel up to 6.18.46/7.1.10/7.2.0 io_uring io_uring_cmd_prep memory leak

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.18.46/7.1.10/7.2.0. This affects the function io_uring_cmd_prep of the component io_uring. Such manipulation leads to memory leak. This vulnerability is uniquely identified as CVE-2026-80811. Local access is required to approach this attack. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.18.46/7.1.10/7.2.0. Affected by this issue is the function io_uring_cmd_prep of the component io_uring. The manipulation with an unknown input leads to a memory leak vulnerability. Using CWE to declare the problem leads to CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: io_uring/cmd: fix iovec leak when the async cmd is not recycled An io_async_cmd carries an iovec array in ->vec.iovec, allocated when the vec has to grow and kept across recycling through ctx->cmd_cache. On two paths nothing frees it and io_clean_op()'s kfree(req->async_data) drops the io_async_cmd without it. io_req_uring_cleanup() clears the async data flags only when io_alloc_cache_put() succeeds, and the cache holds IO_ALLOC_CACHE_MAX == 128 entries, so once it is full the put fails and the vec is left behind. An NVMe passthrough workload gets there without doing anything unusual: nvme_uring_cmd_io() returns -EIOCBQUEUED, so the io_async_cmd stays attached for the lifetime of the command and the live object count tracks the queue depth. Above 128 the puts start failing. ->cleanup is the last chance to free an inherited vec, since io_req_uring_cleanup() returns early for an io-wq issued command and is not called at all for one completed without ever being issued. But io_clean_op() calls ->cleanup only if REQ_F_NEED_CLEANUP is set, and for uring_cmd that happens only where the vec has to grow, so a command reusing a large enough cached vec never sets it. io_rw_alloc_async() and io_msg_alloc_async() flag an inherited vec for exactly this reason; io_uring_cmd_prep() does not. Flag an inherited vec in io_uring_cmd_prep(), and free the vec when the cache put fails, as io_req_rw_cleanup() does. The leak is invisible under KASAN, where io_alloc_cache_vec_kasan() frees the vec unconditionally.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-80811 since 08/26/2026. The exploitation is known to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available.

Upgrading to version 6.18.47, 7.1.11, 7.2.1 or 7.3-rc1 eliminates this vulnerability. Applying the patch b6a768aa975b9ca81b92f028bdd975d1f8237894/b290de4d16d75b6c1ef42025b47f5d94eb1ec09f/7068d3587a64a24943a7c9e232976da2c9e0e303/bb34ae5da3365699d53a756f4c96b6ea9f8ba0c1 is able to eliminate this problem.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory leak
CWE: CWE-401 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.47/7.1.11/7.2.1/7.3-rc1
Patch: b6a768aa975b9ca81b92f028bdd975d1f8237894/b290de4d16d75b6c1ef42025b47f5d94eb1ec09f/7068d3587a64a24943a7c9e232976da2c9e0e303/bb34ae5da3365699d53a756f4c96b6ea9f8ba0c1

Timelineinfo

08/26/2026 CVE reserved
09/04/2026 +9 days Advisory disclosed
09/04/2026 +0 days VulDB entry created
09/04/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-80811 (🔒)
GCVE (CVE): GCVE-0-2026-80811
GCVE (VulDB): GCVE-100-398972

Entryinfo

Created: 09/04/2026 18:38
Changes: 09/04/2026 18:38 (59)
Complete: 🔍
Cache ID: 216::103

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