{"id":"CVE-2026-53362","published":"2026-07-04T12:17:02Z","modified":"2026-10-15T13:46:55Z","title":"Linux Kernel Unspecified Vulnerability","vendor":"Linux","product":"Kernel","tier":"core","eol":null,"description":{"text":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: account for fraggap on the paged allocation path\n\nIn __ip6_append_data(), when the paged-allocation branch is taken\n(MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are\ncomputed as\n\n\talloclen = fragheaderlen + transhdrlen;\n\tpagedlen = datalen - transhdrlen;\n\ndatalen already includes fraggap (datalen = length + fraggap). When\nfraggap is non-zero, this is not the first skb and transhdrlen is zero.\nThe fraggap bytes carried over from the previous skb are copied just past\nthe fragment headers in the new skb's linear area. The linear area is\ntherefore undersized by fraggap bytes while pagedlen is overstated by the\nsame amount, and the copy writes past skb->end into the trailing\nskb_shared_info.\n\nAn unprivileged user can trigger this via a UDPv6 socket using\nMSG_MORE together with MSG_SPLICE_PAGES.\n\nThe bad accounting was introduced by commit 773ba4fe9104 (\"ipv6:\navoid partial copy for zc\"). Before commit ce650a166335 (\"udp6: Fix\n__ip6_append_data()'s handling of MSG_SPLICE_PAGES\"), the negative\ncopy value caused -EINVAL to be returned. That later commit allowed\nMSG_SPLICE_PAGES to proceed in this case, making the corruption\ntriggerable.\n\nThe non-paged branch sets alloclen to fraglen, which already accounts\nfor fraggap because datalen does. Bring the paged branch in line by\nadding fraggap to alloclen and subtracting it from pagedlen.\n\nAfter this adjustment, copy no longer collapses to -fraggap on the\npaged path, so remove the stale comment describing that old arithmetic.\nSince a negative copy is no longer expected for a valid MSG_SPLICE_PAGES\ncase, remove the MSG_SPLICE_PAGES exception from the negative copy check.","provenance":"source","from":"NVD"},"summary":{"text":"The Linux kernel's IPv6 datagram append path (__ip6_append_data() in the ipv6 networking code) miscomputes the linear and paged allocation sizes when fraggap bytes are carried over on the paged allocation branch, causing out-of-bounds writes past the skb's end into its trailing shared info. An attacker with local, low-privilege access can trigger it through a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES, with no user interaction required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:14:59Z"},"cvss":{"score":7.8,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.00709,"percentile":0.53485,"date":"2026-10-30","provenance":"source"},"kev":{"dateAdded":"2026-08-27","dueDate":"2026-08-30","ransomware":false,"requiredAction":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","notes":"This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: ; https://git.kernel.org/stable/c/14200d435af9a9eeb444f529fc2f689a236b7962; https://git.kernel.org/stable/c/65fb14cbebb0cd0eff903a22d33537ddc8b95769; https://git.kernel.org/stable/c/46f201f8b4c39633a1fa3dc12459f506d470993d; https://git.kernel.org/stable/c/6374fb9edf72c67a118a2c214a0dddd04c921e0a; https://git.kernel.org/stable/c/e9eacf19281ea2498b36291b56c9606118c2d74e; https://git.kernel.org/stable/c/736b380e28d0480c7bc3e022f1950f31fe53a7c5 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-53362","provenance":"source"},"vulncheckKev":{"dateAdded":"2026-08-27","exploitedFirstSeen":"2026-08-27","ransomware":false,"evidence":[{"url":"https://euvd.enisa.europa.eu/enisa/EUVD-2026-41669","date":"2026-08-27"},{"url":"https://previdian.com/CVE-2026-53362","date":"2026-08-27"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2026-08-27"},{"url":"https://www.recordedfuture.com/blog/august-2026-cve-landscape","date":"2026-09-08"}],"evidenceTotal":4,"provenance":"source"},"exploited":true,"otx":{"pulseCount":30,"pulses":[{"name":"Actively_Exploited_Kev | Oct 31, 2026","url":"https://otx.alienvault.com/pulse/6ae4aefab0c2191cecd41862","created":"2026-10-30"},{"name":"Actively_Exploited_Kev | Oct 30, 2026","url":"https://otx.alienvault.com/pulse/6ae35d889ea92b4ce19c2680","created":"2026-10-29"},{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"}],"provenance":"machine"},"cwes":[{"id":"CWE-787","name":"Out-of-bounds Write"},{"id":"CWE-122","name":"Heap-based Buffer Overflow"}],"references":[{"url":"https://git.kernel.org/stable/c/14200d435af9a9eeb444f529fc2f689a236b7962","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/46f201f8b4c39633a1fa3dc12459f506d470993d","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/6374fb9edf72c67a118a2c214a0dddd04c921e0a","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/65fb14cbebb0cd0eff903a22d33537ddc8b95769","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/736b380e28d0480c7bc3e022f1950f31fe53a7c5","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/e9eacf19281ea2498b36291b56c9606118c2d74e","tags":["Patch"]},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html","tags":["Third Party Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-53362","tags":["US Government Resource"]}],"techniques":[{"id":"T1068","name":"Exploitation for Privilege Escalation","tactics":["privilege-escalation"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: local unprivileged user triggers kernel memory corruption","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"An unprivileged user can trigger this via a UDPv6 socket","start":789,"end":845}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2026-41669","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-41669","exploited":true,"exploitedSince":"2026-08-27","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":1,"skipped":0,"earliest":"2026-07-03","earliestUrl":"https://github.com/suominen/ipv6_frag_escape","repos":[{"name":"suominen/ipv6_frag_escape","url":"https://github.com/suominen/ipv6_frag_escape","stars":0,"created":"2026-07-03"}]},"first":{"date":"2026-07-03","source":"PoC-in-GitHub","url":"https://github.com/suominen/ipv6_frag_escape"},"provenance":"source"},"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1068"],"provenance":"ai"}],"timeline":[{"date":"2026-07-03","kind":"exploit-public","label":"First public exploit: PoC-in-GitHub","url":"https://github.com/suominen/ipv6_frag_escape","provenance":"source"},{"date":"2026-07-04","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53362","provenance":"source"},{"date":"2026-08-27","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://euvd.enisa.europa.eu/enisa/EUVD-2026-41669","provenance":"source"},{"date":"2026-08-27","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2026-08-27","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-41669","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":"PoC-in-GitHub","daysToKev":54},"priority":{"score":69.2,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":10.0,"detail":"added 65 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":10.7,"detail":"percentile 0.5349"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 PoC-in-GitHub repo"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"30 pulses"},{"name":"CVSS severity","points":5.46,"detail":"base score 7.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]},"lineage":{"familyId":"fam-class-linux-kernel-cwe-787"}}