{"id":"CVE-2026-53362","kind":"vulnerability","aliases":["CVE-2026-53362"],"related":[],"title":"In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged…","description":"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.","summary":"The Linux kernel has an unspecified flaw in its IPv6 networking code that allows privilege escalation. CISA lists it as actively exploited, so an attacker with local code execution can gain root.","severity":"high","cvss":7.8,"epss":null,"exploited":true,"exploited_at":"2026-08-27T00:00:00+00:00","products":[{"name":"linux kernel","fixed":["6.1.177"],"affected":">= 6.0, < 6.1.177","ecosystem":"vendor"},{"name":"linux kernel","fixed":["6.6.144"],"affected":">= 6.2, < 6.6.144","ecosystem":"vendor"},{"name":"linux kernel","fixed":["6.12.95"],"affected":">= 6.7, < 6.12.95","ecosystem":"vendor"},{"name":"linux kernel","fixed":["6.18.38"],"affected":">= 6.13, < 6.18.38","ecosystem":"vendor"},{"name":"linux kernel","fixed":["7.1.3"],"affected":">= 6.19, < 7.1.3","ecosystem":"vendor"},{"name":"siemens simatic s7-1500 tm mfp firmware","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"Linux Kernel","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","infrastructure","kubernetes","linux","red-hat","self-hosted","suse"],"not_affected_if":["kernel-patched","managed-hosting"],"how_to_check":"uname -r to see the running kernel version, then compare it against the fixed kernel builds from your distribution's security advisory for CVE-2026-53362.","fix":"Install the kernel update from your distribution vendor (SUSE, Red Hat, or others named in the advisory) and reboot.","status":"open","published_at":"2026-07-04T12:17:02+00:00","first_seen_at":"2026-10-23T19:11:51+00:00","triaged_at":"2026-10-23T20:31:45+00:00","updated_at":"2026-10-24T00:09:50+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-23T20:31:45Z","model":"claude-haiku-5-5","output":{"fix":"Install the kernel update from your distribution vendor (SUSE, Red Hat, or others named in the advisory) and reboot.\nunknown","summary":"The Linux kernel has an unspecified flaw in its IPv6 networking code that allows privilege escalation. CISA lists it as actively exploited, so an attacker with local code execution can gain root.","category":"infrastructure","who_cares":["linux","self-hosted","kubernetes","suse","red-hat"],"confidence":0.6,"analyst_note":"Find the fixed kernel versions per distro and whether IPv6 must be enabled to be exploitable; see the CISA KEV entry and vendor advisories for CVE-2026-53362.","how_to_check":"uname -r to see the running kernel version, then compare it against the fixed kernel builds from your distribution's security advisory for CVE-2026-53362.\nunknown","needs_analyst":true,"not_affected_if":["managed-hosting","kernel-patched"],"severity_if_unknown":"high"},"cost_usd":0.000396,"input_tokens":2214,"output_tokens":350,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-1500':37A '-2026':19A,22A '-53362':20A,23A '773ba4fe9104':237C 'account':12A,97C,232C,294C 'activ':74B 'add':307C 'adjust':318C 'alloc':103C,113C 'alloclen':124C,130C,289C,310C 'allow':67B,270C 'alreadi':137C,293C 'amount':198C 'append':107C,250C 'area':181C,184C 'arithmet':337C 'attack':78B 'avoid':239C 'bad':231C 'branch':114C,287C,303C 'bring':300C 'byte':161C,190C 'carri':162C 'case':278C,352C 'caus':262C 'ce650a166335':246C 'check':363C 'cisa':70B 'code':65B,81B 'collaps':322C 'comment':333C 'commit':236C,245C,269C 'comput':128C 'copi':169C,201C,241C,260C,319C,341C,362C 'corrupt':281C 'cve':18A,21A 'data':108C,251C 'datalen':134C,136C,140C,298C 'describ':334C 'einval':263C 'end':205C 'escal':69B 'except':358C 'execut':82B 'expect':345C 'exploit':43B,75B 'f':120C 'firmware':40A 'first':153C 'fix':248C 'flaw':60B 'follow':6A,91C 'fraggap':14A,99C,139C,142C,144C,160C,189C,296C,308C,324C 'fragheaderlen':131C 'fraglen':123C,291C 'fragment':173C 'gain':84B 'handl':253C 'hat':49B 'header':174C 'host':52B 'includ':138C 'info':211C 'infrastructur':44B 'introduc':234C 'ip6':106C,249C 'ipv6':11A,63B,96C,238C 'kernel':4A,25A,27A,29A,31A,33A,42A,56B,89C 'kubernet':45B 'larg':122C 'later':268C 'length':141C 'line':305C 'linear':180C,183C 'linux':3A,24A,26A,28A,30A,32A,41A,46B,55B,88C 'list':71B 'local':80B 'longer':321C,344C 'make':279C 'mfp':39A 'msg':117C,223C,227C,255C,271C,349C,355C 'negat':259C,340C,361C 'netif':119C 'network':64B 'new':177C 'non':147C,285C 'non-pag':284C 'non-zero':146C 'old':336C 'overst':194C 'page':17A,102C,112C,229C,257C,273C,286C,302C,327C,351C,357C 'paged-alloc':111C 'pagedlen':126C,133C,192C,315C 'partial':240C 'past':171C,203C 'path':104C,328C 'previous':166C 'privileg':68B 'proceed':275C 'red':48B 'red-hat':47B 'remov':330C,353C 'resolv':10A,95C 'return':266C 'root':85B 's7':36A 'self':51B 'self-host':50B 'set':288C 'sg':121C 'share':210C 'siemens':34A 'simatic':35A 'sinc':338C 'skb':154C,167C,178C,204C,209C 'socket':221C 'splice':228C,256C,272C,350C,356C 'stale':332C 'subtract':312C 'suse':53B 'taken':116C 'therefor':186C 'tm':38A 'togeth':225C 'trail':208C 'transhdrlen':132C,135C,156C 'trigger':216C,282C 'udp6':247C 'udpv6':220C 'unders':187C 'unprivileg':213C 'unspecifi':59B 'use':222C 'user':214C 'valid':348C 'valu':261C 'via':218C 'vulner':7A,92C 'write':202C 'zc':243C 'zero':148C,158C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2026-07-04T12:17:02+00:00","kev":{"dateAdded":"2026-08-27","dueDate":"2026-08-30","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.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvss_by":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2026-53362","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-53362","severity":null,"published_at":"2026-08-27T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:51+00:00","fetched_at":"2026-10-25T12:39:21+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-53362","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53362","severity":null,"published_at":"2026-07-04T12:17:02+00:00","modified_at":"2026-10-15T13:46:55+00:00","first_seen_at":"2026-10-23T23:44:52+00:00","fetched_at":"2026-10-23T23:44:52+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}