{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89720", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.752Z", "datePublished": "2026-09-11T19:46:32.923Z", "dateUpdated": "2026-09-11T19:46:32.923Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-11T19:46:32.923Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nubifs: fix out-of-bounds read in signature length check\n\nubifs_sb_verify_signature() bounds the on-disk ubifs_sig_node->len field\nbefore handing the signature payload to verify_pkcs7_signature(), but the\ncheck has the wrong sign:\n\n\tif (le32_to_cpu(signode->len) > snod->len + sizeof(struct ubifs_sig_node))\n\nThe signature bytes start sizeof(struct ubifs_sig_node) (UBIFS_SIG_NODE_SZ,\n64 bytes) into the node, so the payload is at most\n\n\tsnod->len - sizeof(struct ubifs_sig_node)\n\nbytes long. Adding the header size instead of subtracting it accepts a\ndeclared length up to 2 * UBIFS_SIG_NODE_SZ larger than the node actually\nholds -- past the end of c->sbuf, which is vmalloc(c->leb_size).\nverify_pkcs7_signature() -> pkcs7_parse_message() -> asn1_ber_decoder()\nis then handed that inflated length and reads beyond the allocation while\nwalking the DER headers. The node length comes straight from the mounted\nimage, so a crafted signed UBIFS image reaches this via\nubifs_read_superblock() before the signature is cryptographically checked.\n\nsnod->len is guaranteed to be >= UBIFS_SIG_NODE_SZ by the node scanner\n(c->ranges[UBIFS_SIG_NODE].min_len == UBIFS_SIG_NODE_SZ), so the corrected\nsubtraction cannot underflow. Legitimately signed images are unaffected: a\ncorrect superblock never declares a signature longer than the node it is\nembedded in."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/ubifs/auth.c"], "versions": [{"version": "817aa094842dfc3a6b98c9582d4a647827f66201", "lessThan": "f76b79d6e42af20682495bccd22f72c7164b0018", "status": "affected", "versionType": "git"}, {"version": "817aa094842dfc3a6b98c9582d4a647827f66201", "lessThan": "a1dc246f98bb94233effa4fa3ec7bf84700bb7d1", "status": "affected", "versionType": "git"}, {"version": "817aa094842dfc3a6b98c9582d4a647827f66201", "lessThan": "83e1aa9f5f906c9b1f4949d0521f0f950a159d96", "status": "affected", "versionType": "git"}, {"version": "817aa094842dfc3a6b98c9582d4a647827f66201", "lessThan": "95d27c1708bb6e8823c8e7c623f9abc2a91bf4bf", "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/ubifs/auth.c"], "versions": [{"version": "5.3", "status": "affected"}, {"version": "0", "lessThan": "5.3", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3-rc1", "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": "5.3", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "7.3-rc1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/f76b79d6e42af20682495bccd22f72c7164b0018"}, {"url": "https://git.kernel.org/stable/c/a1dc246f98bb94233effa4fa3ec7bf84700bb7d1"}, {"url": "https://git.kernel.org/stable/c/83e1aa9f5f906c9b1f4949d0521f0f950a159d96"}, {"url": "https://git.kernel.org/stable/c/95d27c1708bb6e8823c8e7c623f9abc2a91bf4bf"}], "title": "ubifs: fix out-of-bounds read in signature length check", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/ubifs/auth.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "f76b79d6e42af20682495bccd22f72c7164b0018", "status": "affected", "version": "817aa094842dfc3a6b98c9582d4a647827f66201", "versionType": "git"}, {"lessThan": "a1dc246f98bb94233effa4fa3ec7bf84700bb7d1", "status": "affected", "version": "817aa094842dfc3a6b98c9582d4a647827f66201", "versionType": "git"}, {"lessThan": "83e1aa9f5f906c9b1f4949d0521f0f950a159d96", "status": "affected", "version": "817aa094842dfc3a6b98c9582d4a647827f66201", "versionType": "git"}, {"lessThan": "95d27c1708bb6e8823c8e7c623f9abc2a91bf4bf", "status": "affected", "version": "817aa094842dfc3a6b98c9582d4a647827f66201", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/ubifs/auth.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "5.3"}, {"lessThan": "5.3", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.109", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3-rc1", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nubifs: fix out-of-bounds read in signature length check\n\nubifs_sb_verify_signature() bounds the on-disk ubifs_sig_node->len field\nbefore handing the signature payload to verify_pkcs7_signature(), but the\ncheck has the wrong sign:\n\n\tif (le32_to_cpu(signode->len) > snod->len + sizeof(struct ubifs_sig_node))\n\nThe signature bytes start sizeof(struct ubifs_sig_node) (UBIFS_SIG_NODE_SZ,\n64 bytes) into the node, so the payload is at most\n\n\tsnod->len - sizeof(struct ubifs_sig_node)\n\nbytes long. Adding the header size instead of subtracting it accepts a\ndeclared length up to 2 * UBIFS_SIG_NODE_SZ larger than the node actually\nholds -- past the end of c->sbuf, which is vmalloc(c->leb_size).\nverify_pkcs7_signature() -> pkcs7_parse_message() -> asn1_ber_decoder()\nis then handed that inflated length and reads beyond the allocation while\nwalking the DER headers. The node length comes straight from the mounted\nimage, so a crafted signed UBIFS image reaches this via\nubifs_read_superblock() before the signature is cryptographically checked.\n\nsnod->len is guaranteed to be >= UBIFS_SIG_NODE_SZ by the node scanner\n(c->ranges[UBIFS_SIG_NODE].min_len == UBIFS_SIG_NODE_SZ), so the corrected\nsubtraction cannot underflow. Legitimately signed images are unaffected: a\ncorrect superblock never declares a signature longer than the node it is\nembedded in."}], "id": "CVE-2026-89720", "lastModified": "2026-09-11T20:20:00.943", "metrics": {}, "published": "2026-09-11T20:20:00.943", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/83e1aa9f5f906c9b1f4949d0521f0f950a159d96"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/95d27c1708bb6e8823c8e7c623f9abc2a91bf4bf"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a1dc246f98bb94233effa4fa3ec7bf84700bb7d1"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f76b79d6e42af20682495bccd22f72c7164b0018"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: Out-of-bounds read in UBIFS signature length check", "id": "2532147", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532147"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.7", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H", "status": "draft"}, "cwe": "CWE-125", "details": ["A flaw was found in the Linux kernel's Unsorted Block Image File System (UBIFS). An incorrect bounds check in the ubifs_sb_verify_signature() function allows a crafted signed UBIFS image to declare a signature length larger than its actual size. This can lead to an out-of-bounds read when processing the signature, potentially causing information disclosure or a system crash (Denial of Service)."], "name": "CVE-2026-89720", "public_date": "2026-09-11T19:46:32Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89720\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89720\nhttps://git.kernel.org/stable/c/83e1aa9f5f906c9b1f4949d0521f0f950a159d96\nhttps://git.kernel.org/stable/c/95d27c1708bb6e8823c8e7c623f9abc2a91bf4bf\nhttps://git.kernel.org/stable/c/a1dc246f98bb94233effa4fa3ec7bf84700bb7d1\nhttps://git.kernel.org/stable/c/f76b79d6e42af20682495bccd22f72c7164b0018"], "threat_severity": "Moderate"}

{}