CVE-2026-23416

Description

In the Linux kernel, the following vulnerability has been resolved: mm/mseal: update VMA end correctly on merge Previously we stored the end of the current VMA in curr_end, and then upon iterating to the next VMA updated curr_start to curr_end to advance to the next VMA. However, this doesn't take into account the fact that a VMA might be updated due to a merge by vma_modify_flags(), which can result in curr_end being stale and thus, upon setting curr_start to curr_end, ending up with an incorrect curr_start on the next iteration. Resolve the issue by setting curr_end to vma->vm_end unconditionally to ensure this value remains updated should this occur. While we're here, eliminate this entire class of bug by simply setting const curr_[start/end] to be clamped to the input range and VMAs, which also happens to simplify the logic.

CVSS Details

CVSS Score

5.5

Severity

MEDIUM

CVSS Vector

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

Configurations (Affected Products)

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

cpe:2.3:o:linux:linux_kernel:6.17:-:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* - VULNERABLE

Linux Kernel (包含mseal补丁的版本)

PoC / Exploit Code

⚠ For Security Research Only

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

python

#include <sys/mman.h>
#include <unistd.h>

// Conceptual PoC for CVE-2026-23416
// This attempts to trigger the VMA merge bug in mm/mseal.

int main() {
    void *ptr;
    // Step 1: Create a memory mapping
    ptr = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
    if (ptr == MAP_FAILED) return 1;

    // Step 2: Seal the VMA (requires mseal syscall)
    // mseal(ptr, 4096, MSEAL_PROT_PKEY);
    
    // Step 3: Perform operations that might trigger a merge
    // e.g., mprotect or munmap adjacent regions while iterating
    // This logic is highly dependent on internal kernel state.
    
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-23416
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-23416
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-23416/
[4] VulDB https://vuldb.com/cve/CVE-2026-23416
[5] https://git.kernel.org/stable/c/2697dd8ae721db4f6a53d4f4cbd438212a80f8dc
[6] https://git.kernel.org/stable/c/40b3f4700e5535fbe74738cebb9379a40ec66bed
[7] https://git.kernel.org/stable/c/83737e34b83a23b2a9bcf586b058b2c2a54c7c6b

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-23416", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-02T12:16:20.960", "lastModified": "2026-04-24T15:21:59.490", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/mseal: update VMA end correctly on merge\n\nPreviously we stored the end of the current VMA in curr_end, and then upon\niterating to the next VMA updated curr_start to curr_end to advance to the\nnext VMA.\n\nHowever, this doesn't take into account the fact that a VMA might be\nupdated due to a merge by vma_modify_flags(), which can result in curr_end\nbeing stale and thus, upon setting curr_start to curr_end, ending up with\nan incorrect curr_start on the next iteration.\n\nResolve the issue by setting curr_end to vma->vm_end unconditionally to\nensure this value remains updated should this occur.\n\nWhile we're here, eliminate this entire class of bug by simply setting\nconst curr_[start/end] to be clamped to the input range and VMAs, which\nalso happens to simplify the logic."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17.1", "versionEndExcluding": "6.18.21", "matchCriteriaId": "44CB3599-9974-4F35-B3CC-580CAC6FA38B"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.11", "matchCriteriaId": "4CA2E747-A9EC-4518-9AA2-B4247FC748B7"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:-:*:*:*:*:*:*", "matchCriteriaId": "7CC8B11D-82DC-4958-8DC7-BF5CC829A5E9"}, {"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:7.0:rc7:*:*:*:*:*:*", "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/2697dd8ae721db4f6a53d4f4cbd438212a80f8dc", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/40b3f4700e5535fbe74738cebb9379a40ec66bed", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/83737e34b83a23b2a9bcf586b058b2c2a54c7c6b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}