{"id":"AZL-99588","summary":"CVE-2026-80847 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: clamp route advmss to TCP_MIN_MSS\n\ntcp_select_initial_window() assumes that callers never pass an MSS\nsmaller than 1, but route-derived advmss values can violate that\nassumption.\n\nA too-small explicit RTAX_ADVMSS is one way to get there, but it is not\nthe only one. The same divide-by-zero can also be reached through the\n\"default advmss\" path when RTAX_ADVMSS is left at 0 and the effective\nadvmss is later driven down by route MTU and min_adv_mss.\n\nIntroduce a tcp_dst_advmss() helper that clamps route advmss to\nTCP_MIN_MSS before TCP consumes it, and use it in the TCP paths that\nderive advmss from dst metrics. This keeps the effective MSS from\ndropping to zero before tcp_select_initial_window() rounds the receive\nwindow.","modified":"2026-09-07T05:28:29Z","published":"2026-09-04T16:18:13Z","upstream":["CVE-2026-80847"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80847"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-99588.json"}}],"schema_version":"1.9.0"}