{"id":"CVE-2026-46300","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-46300","generatedAt":"2026-10-31T02:44:24.008Z","title":"Linux Kernel Missing Initialization of a Variable Vulnerability","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: skbuff: preserve shared-frag marker during coalescing\n\nskb_try_coalesce() can attach paged frags from @from to @to.  If @from\nhas SKBFL_SHARED_FRAG set, the resulting @to skb can contain the same\nexternally-owned or page-cache-backed frags, but the shared-frag marker\nis currently lost.\n\nThat breaks the invariant relied on by later in-place writers.  In\nparticular, ESP input checks skb_has_shared_frag() before deciding\nwhether an uncloned nonlinear skb can skip skb_cow_data().  If TCP\nreceive coalescing has moved shared frags into an unmarked skb, ESP can\nsee skb_has_shared_frag() as false and decrypt in place over page-cache\nbacked frags.\n\nPropagate SKBFL_SHARED_FRAG when skb_try_coalesce() transfers paged\nfrags.  The tailroom copy path does not need the marker because it copies\nbytes into @to's linear data rather than transferring frag descriptors.","published":"2026-05-23T12:17:03.000Z","lastModified":"2026-10-29T17:30:34.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-787","CWE-456","CWE-123"],"affected":["linux/linux kernel","siemens/simatic s7-1500 cpu 1518-4 pn\\/dp mfp firmware","redhat/openshift container platform","redhat/enterprise linux","redhat/enterprise linux aus","redhat/enterprise linux eus","redhat/enterprise linux tus","redhat/enterprise linux update services for sap solutions"],"epss":{"score":0.15719,"percentile":0.96854,"date":"2026-10-29","history":[{"date":"2026-09-24","score":0.02425,"percentile":0.83495},{"date":"2026-10-25","score":0.10192,"percentile":0.95635},{"date":"2026-10-29","score":0.15719,"percentile":0.96854}]},"kev":{"listed":true,"dateAdded":"2026-10-28","dueDate":"2026-10-31","knownRansomwareCampaignUse":"Unknown","notes":"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.\nThis 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/3599e6b3cc1ada96883d496a50a210d3afbb6987 ; https://git.kernel.org/stable/c/2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c ; https://git.kernel.org/stable/c/9d3e5fd19fe1063bf607219e8562fbd567b8e8d5 ; https://git.kernel.org/stable/c/78bf6b6bb19541d19fbda6242e7cfe2c682763c0 ; https://git.kernel.org/stable/c/760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e ; https://git.kernel.org/stable/c/3bd9e113d50034db99d7ef69fd8e5242d15e414a ; https://git.kernel.org/stable/c/3884358a9286b17f389a72b1426fc4547c23c111 ; https://git.kernel.org/stable/c/f84eca5817390257cef78013d0112481c503b4a3 ; 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-2026-46300"},"exploits":{"count":1,"verified":false,"firstPublished":"2026-05-29","source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[{"edbId":52591,"kind":"exploit","title":"Linux Kernel -  Local Privilege Escalation","url":"https://www.exploit-db.com/exploits/52591","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/linux/local/52591.txt","file":"exploits/linux/local/52591.txt","published":"2026-05-29","added":"2026-05-29","updated":"2026-05-29","author":"nu11secur1ty","type":"local","platform":"linux","port":null,"verified":false,"codes":["CVE-2026-46300","CVE-2026-43500","CVE-2026-43284"],"tags":null,"aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":null}]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 31 October 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[{"kind":"epss","label":"EPSS jump","at":"2026-10-29T00:00:00.000Z","detail":{"to":0.15719,"from":0.10192,"percentile":0.96854},"summary":"EPSS moved from 10.2% to 15.7% probability of exploitation in the next thirty days."},{"kind":"kev","label":"Added to KEV","at":"2026-10-28T00:00:00.000Z","detail":{"name":"Linux Kernel Missing Initialization of a Variable Vulnerability","vendor":"Linux","dueDate":"2026-10-31","product":"Kernel","ransomware":"Unknown"},"summary":"Added to CISA KEV — known to be exploited; federal remediation due 2026-10-31."},{"kind":"epss","label":"EPSS jump","at":"2026-10-25T00:00:00.000Z","detail":{"to":0.10192,"from":0.02425,"percentile":0.95635},"summary":"EPSS moved from 2.4% to 10.2% probability of exploitation in the next thirty days."}],"references":[{"url":"https://git.kernel.org/stable/c/2f2b16022a2e10ca7bccfb98db5ed2ec0f72641c","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3599e6b3cc1ada96883d496a50a210d3afbb6987","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3884358a9286b17f389a72b1426fc4547c23c111","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3bd9e113d50034db99d7ef69fd8e5242d15e414a","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/760e1addc27ba1a7beb4a0a7e8b3e9ec49e7a34e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/78bf6b6bb19541d19fbda6242e7cfe2c682763c0","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9d3e5fd19fe1063bf607219e8562fbd567b8e8d5","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f84eca5817390257cef78013d0112481c503b4a3","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"http://www.openwall.com/lists/oss-security/2026/05/13/5","tags":["Mailing 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