CVE-2026-31694

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-31694", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.131Z", "datePublished": "2026-05-01T13:53:36.048Z", "dateUpdated": "2026-10-15T01:17:53.619Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:24:32.263Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfuse: reject oversized dirents in page cache\n\nfuse_add_dirent_to_cache() computes a serialized dirent size from the\nserver-controlled namelen field and copies the dirent into a single\npage-cache page. The existing logic only checks whether the dirent fits\nin the remaining space of the current page and advances to a fresh page\nif not. It never checks whether the dirent itself exceeds PAGE_SIZE.\n\nAs a result, a malicious FUSE server can return a dirent with\nnamelen=4095, producing a serialized record size of 4120 bytes. On 4 KiB\npage systems this causes memcpy() to overflow the cache page by 24 bytes\ninto the following kernel page.\n\nReject dirents that cannot fit in a single page before copying them into\nthe readdir cache."}], "metrics": [{"cvssV3_1": {"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"}, "scenarios": [{"lang": "en", "value": "AV:L - The vulnerable path is reached through local filesystem operations on a FUSE mount, with malicious replies supplied via a local /dev/fuse userspace daemon rather than directly by network packets.\nAC:L - A malicious FUSE server can deterministically set FOPEN_CACHE_DIR and return a dirent with namelen=4095; the overflow occurs during ordinary readdir/getdents on common 4 KiB page systems.\nPR:L - An unprivileged local user can plausibly run and access their own FUSE filesystem, including through user-namespace-capable FUSE mounts where available, and does not need real init-namespace root.\nUI:N - The malicious local mounter can trigger getdents/readdir on their own FUSE directory without requiring a separate victim action.\nS:U - The bug is kernel memory corruption within the same host kernel security authority and does not cross a VM, IOMMU, or similar scope boundary.\nC:H - The bug is an attacker-controlled out-of-bounds write into the following kernel page, and such kernel memory corruption can be leveraged to expose sensitive kernel or process memory.\nI:H - The attacker controls the oversized serialized dirent bytes copied past the cache page, giving a kernel memory corruption primitive that can plausibly be developed into arbitrary modification or code execution.\nA:H - The overflow can corrupt adjacent kernel memory or fault during the memcpy/kmap access path, making kernel oops, panic, or system instability a high-impact availability outcome."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/fuse/readdir.c"], "versions": [{"version": "27992ef80770d61a57f6c3a551735b08cefdffa3", "lessThan": "7de93abfaae1b2dc94da8a07a36421bd073f1d8f", "status": "affected", "versionType": "git"}, {"version": "27992ef80770d61a57f6c3a551735b08cefdffa3", "lessThan": "474ce83c96a55f2eeb14dee2be375eeadfdacdf5", "status": "affected", "versionType": "git"}, {"version": "27992ef80770d61a57f6c3a551735b08cefdffa3", "lessThan": "51a8de6c50bf947c8f534cd73da4c8f0a13e7bed", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/fuse/readdir.c"], "versions": [{"version": "6.15", "status": "affected"}, {"version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.25", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.2", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.18.25"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.0.2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/7de93abfaae1b2dc94da8a07a36421bd073f1d8f"}, {"url": "https://git.kernel.org/stable/c/474ce83c96a55f2eeb14dee2be375eeadfdacdf5"}, {"url": "https://git.kernel.org/stable/c/51a8de6c50bf947c8f534cd73da4c8f0a13e7bed"}], "title": "fuse: reject oversized dirents in page cache", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"x_adpType": "supplier", "providerMetadata": {"orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-10-15T01:17:53.619Z"}, "affected": [{"vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "versions": [{"status": "affected", "version": "0", "lessThan": "*", "versionType": "custom"}], "defaultStatus": "unknown"}], "references": [{"url": "https://cert-portal.siemens.com/productcert/html/ssa-784472.html"}]}]}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/fuse/readdir.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "7de93abfaae1b2dc94da8a07a36421bd073f1d8f", "status": "affected", "version": "27992ef80770d61a57f6c3a551735b08cefdffa3", "versionType": "git"}, {"lessThan": "474ce83c96a55f2eeb14dee2be375eeadfdacdf5", "status": "affected", "version": "27992ef80770d61a57f6c3a551735b08cefdffa3", "versionType": "git"}, {"lessThan": "51a8de6c50bf947c8f534cd73da4c8f0a13e7bed", "status": "affected", "version": "27992ef80770d61a57f6c3a551735b08cefdffa3", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/fuse/readdir.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.15"}, {"lessThan": "6.15", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.25", "versionType": "semver"}, {"lessThanOrEqual": "7.0.*", "status": "unaffected", "version": "7.0.2", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.1", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"affectedData": [{"defaultStatus": "unknown", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "vendor": "Siemens", "versions": [{"lessThan": "*", "status": "affected", "version": "0", "versionType": "custom"}]}], "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "F2D3B79E-3EFA-4203-9F11-FF77FD2FBA79", "versionEndExcluding": "6.18.25", "versionStartIncluding": "6.15", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "1BD58F1E-7C20-4C0D-92A2-FAC5CBFBE8A8", "versionEndExcluding": "7.0.2", "versionStartIncluding": "6.19", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*", "matchCriteriaId": "B1EF7059-E670-45F4-B422-54C40FA86390", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*", "matchCriteriaId": "0D38F0BF-A728-4133-A358-D44A2F7EE6D6", "vulnerable": true}], "negate": false, "operator": "OR"}]}, {"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:siemens:simatic_s7-1500_tm_mfp_firmware:-:*:*:*:*:*:*:*", "matchCriteriaId": "7F6C0262-1527-4F55-8BDE-973F59FE7E1B", "vulnerable": true}], "negate": false, "operator": "OR"}, {"cpeMatch": [{"criteria": "cpe:2.3:h:siemens:simatic_s7-1500_tm_mfp:-:*:*:*:*:*:*:*", "matchCriteriaId": "754051AB-27D3-41CA-B2C8-79BAD48C8750", "vulnerable": false}], "negate": false, "operator": "OR"}], "operator": "AND"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfuse: reject oversized dirents in page cache\n\nfuse_add_dirent_to_cache() computes a serialized dirent size from the\nserver-controlled namelen field and copies the dirent into a single\npage-cache page. The existing logic only checks whether the dirent fits\nin the remaining space of the current page and advances to a fresh page\nif not. It never checks whether the dirent itself exceeds PAGE_SIZE.\n\nAs a result, a malicious FUSE server can return a dirent with\nnamelen=4095, producing a serialized record size of 4120 bytes. On 4 KiB\npage systems this causes memcpy() to overflow the cache page by 24 bytes\ninto the following kernel page.\n\nReject dirents that cannot fit in a single page before copying them into\nthe readdir cache."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nfuse: rechazar entradas de directorio de tama\u00f1o excesivo en la cach\u00e9 de p\u00e1ginas\n\nfuse_add_dirent_to_cache() calcula un tama\u00f1o de entrada de directorio serializado a partir del campo \u2019namelen\u2019 controlado por el servidor y copia la entrada de directorio en una \u00fanica p\u00e1gina de la cach\u00e9 de p\u00e1ginas. La l\u00f3gica existente solo verifica si la entrada de directorio cabe en el espacio restante de la p\u00e1gina actual y avanza a una p\u00e1gina nueva si no es as\u00ed. Nunca verifica si la propia entrada de directorio excede PAGE_SIZE.\n\nComo resultado, un servidor FUSE malicioso puede devolver una entrada de directorio con namelen=4095, produciendo un tama\u00f1o de registro serializado de 4120 bytes. En sistemas con p\u00e1ginas de 4 KiB, esto provoca que memcpy() desborde la p\u00e1gina de cach\u00e9 en 24 bytes hacia la siguiente p\u00e1gina del kernel.\n\nRechazar entradas de directorio que no pueden caber en una sola p\u00e1gina antes de copiarlas en la cach\u00e9 de readdir."}], "id": "CVE-2026-31694", "lastModified": "2026-11-11T21:10:00.200", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-05-01T14:16:19.133", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/474ce83c96a55f2eeb14dee2be375eeadfdacdf5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/51a8de6c50bf947c8f534cd73da4c8f0a13e7bed"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/7de93abfaae1b2dc94da8a07a36421bd073f1d8f"}, {"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "tags": ["Third Party Advisory"], "url": "https://cert-portal.siemens.com/productcert/html/ssa-784472.html"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: fuse: reject oversized dirents in page cache", "id": "2464503", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2464503"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-1284", "details": ["A flaw was found in the Linux kernel's Filesystem in Userspace (FUSE) component. A malicious FUSE server could exploit this by providing an oversized directory entry (dirent) that is not properly validated. This improper validation causes a memory copy operation to write beyond the allocated buffer, leading to a 24-byte overflow into an adjacent kernel memory page. This memory corruption could potentially lead to information disclosure or other unpredictable system behavior."], "name": "CVE-2026-31694", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-05-01T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-31694\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-31694\nhttps://lore.kernel.org/linux-cve-announce/2026050139-CVE-2026-31694-f974@gregkh/T"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[69e34551152a286f827d54dcb5700da6aeaac1fb,d23ad78bfd205eac26766e38ba7d79f279131098)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[69e34551152a286f827d54dcb5700da6aeaac1fb,45c05af36311624c1148123caeb011312495d86b)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[69e34551152a286f827d54dcb5700da6aeaac1fb,7de93abfaae1b2dc94da8a07a36421bd073f1d8f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[69e34551152a286f827d54dcb5700da6aeaac1fb,474ce83c96a55f2eeb14dee2be375eeadfdacdf5)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[69e34551152a286f827d54dcb5700da6aeaac1fb,51a8de6c50bf947c8f534cd73da4c8f0a13e7bed)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.20"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,4.20)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.136,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.84,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.25,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.2,7.1.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-05-01T20:30:05.026753+00:00", "updated": "2026-05-06T22:00:14.069125+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}