Linux Kernel up to 6.12.111/6.18.54/7.2.8/7.3-rc4 MCTP mctp_lookup_prealloc_tag allocation of resources

CVSS Meta Temp Score
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CTI Interest Score
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5.2$0-$5k0.00-

Summaryinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 6.12.111/6.18.54/7.2.8/7.3-rc4. Affected is the function mctp_lookup_prealloc_tag of the component MCTP. The manipulation results in allocation of resources. This vulnerability is cataloged as CVE-2026-98525. The attack may be launched remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in Linux Kernel up to 6.12.111/6.18.54/7.2.8/7.3-rc4. Affected is the function mctp_lookup_prealloc_tag of the component MCTP. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. This is going to have an impact on integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: mctp: route: iterate socket tag list in mctp_lookup_prealloc_tag() When a socket transmits a packet with MCTP_TAG_PREALLOC set, mctp_lookup_prealloc_tag() iterates over the per-netns &mns->keys list and matches netid, req_tag, peer_addr, and manual_alloc, without checking whether tmp->sk == &msk->sk. This allows any MCTP socket in the same network namespace to use and consume another socket's preallocated tag. Iterate the socket's own tag list (&msk->keys via sklist) instead of the namespace-wide &mns->keys list in mctp_lookup_prealloc_tag(), ensuring that only tags allocated by msk are matched. Tested in QEMU against Linux 7.3.0-rc3 by allocating a manual tag (0x18) on socket A via SIOCMCTPALLOCTAG for peer EID 9 and sending a 4-byte message with MCTP_TAG_PREALLOC from socket B in the same network namespace. On the unfixed kernel, sendto(sock_b) using socket A's preallocated tag succeeds (ret = 4); with this patch applied, sendto(sock_b) fails with -ENOENT (errno = 2) while sendto(sock_a) succeeds (ret = 4).

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-98525 since 09/25/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 10/18/2026). This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 6.12.112, 6.18.55, 7.2.9 or 7.3-rc5 eliminates this vulnerability. Applying the patch 09299addab11857e92eca55cd8ef3350b927c90c/e35cb500dd14882f8dee61783fccd1823fd3ab0d/f178300e2f56ca9ec2a3a0090608730bbee0af7b/26cc0e69cce062cd3aa6fae33074684669c35a71 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.2

VulDB Base Score: 5.4
VulDB Temp Score: 5.2
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: Allocation of resources
CWE: CWE-770 / CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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 6.12.112/6.18.55/7.2.9/7.3-rc5
Patch: 09299addab11857e92eca55cd8ef3350b927c90c/e35cb500dd14882f8dee61783fccd1823fd3ab0d/f178300e2f56ca9ec2a3a0090608730bbee0af7b/26cc0e69cce062cd3aa6fae33074684669c35a71

Timelineinfo

09/25/2026 CVE reserved
10/18/2026 +23 days Advisory disclosed
10/18/2026 +0 days VulDB entry created
10/18/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98525 (🔒)
GCVE (CVE): GCVE-0-2026-98525
GCVE (VulDB): GCVE-100-421794

Entryinfo

Created: 10/18/2026 17:51
Changes: 10/18/2026 17:51 (59)
Complete: 🔍
Cache ID: 216::103

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