CVE-2026-31435

Description

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix read abandonment during retry Under certain circumstances, all the remaining subrequests from a read request will get abandoned during retry. The abandonment process expects the 'subreq' variable to be set to the place to start abandonment from, but it doesn't always have a useful value (it will be uninitialised on the first pass through the loop and it may point to a deleted subrequest on later passes). Fix the first jump to "abandon:" to set subreq to the start of the first subrequest expected to need retry (which, in this abandonment case, turned out unexpectedly to no longer have NEED_RETRY set). Also clear the subreq pointer after discarding superfluous retryable subrequests to cause an oops if we do try to access it.

CVSS Details

CVSS Score

8.8

Severity

HIGH

CVSS Vector

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

Configurations (Affected Products)

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

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

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

cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* - VULNERABLE

Linux Kernel (具体受影响版本请参考Git提交记录)

PoC / Exploit Code

⚠ For Security Research Only

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

python

// Pseudo-code demonstrating the vulnerability logic
// Triggering a netfs read retry scenario

void trigger_vulnerability() {
    // Simulate netfs read request and retry condition
    struct netfs_read_request *rreq;
    struct netfs_read_subrequest *subreq; // Vulnerable: uninitialized
    
    // ... setup ...

    // Simulate condition causing jump to abandon
    if (needs_retry) {
        goto abandon; // subreq is not initialized here
    }
    
    // Normal flow...
    return;

abandon:
    // BUG: Using uninitialized or stale subreq pointer
    // leads to kernel panic (Oops)
    process_subrequests(subreq); 
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-31435
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-31435
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-31435/
[4] VulDB https://vuldb.com/cve/CVE-2026-31435
[5] https://git.kernel.org/stable/c/3e5fd8f53b575ff2188f82071da19c977ca56c41
[6] https://git.kernel.org/stable/c/7e57523490cd2efb52b1ea97f2e0a74c0fb634cd
[7] https://git.kernel.org/stable/c/8f2f2bd128a8d9edbc1e785760da54ada3df69b7

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-31435", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-22T14:16:36.710", "lastModified": "2026-05-19T22:12:35.560", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix read abandonment during retry\n\nUnder certain circumstances, all the remaining subrequests from a read\nrequest will get abandoned during retry. The abandonment process expects\nthe 'subreq' variable to be set to the place to start abandonment from, but\nit doesn't always have a useful value (it will be uninitialised on the\nfirst pass through the loop and it may point to a deleted subrequest on\nlater passes).\n\nFix the first jump to \"abandon:\" to set subreq to the start of the first\nsubrequest expected to need retry (which, in this abandonment case, turned\nout unexpectedly to no longer have NEED_RETRY set).\n\nAlso clear the subreq pointer after discarding superfluous retryable\nsubrequests to cause an oops if we do try to access it."}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12", "versionEndExcluding": "6.18.21", "matchCriteriaId": "93477C16-86F4-42D8-A83F-3E95FF0B26F8"}, {"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: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"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/3e5fd8f53b575ff2188f82071da19c977ca56c41", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/7e57523490cd2efb52b1ea97f2e0a74c0fb634cd", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/8f2f2bd128a8d9edbc1e785760da54ada3df69b7", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}