{"apiVersion":"1.0","identifier":"CVE-2026-74478","description":"In the Linux kernel, the following vulnerability has been resolved: um: vector: fix use-after-free in vector_mmsg_rx() When vector_mmsg_rx() discards a packet whose overlay header fails verify_header(), it frees the skb and continues the loop: if (header_check < 0) { dev_kfree_skb_irq(skb); vp->estats.rx_encaps_errors++; continue; } The normal and short-packet paths fall through to the bottom of the loop body, which clears the consumed slot and advances the cursors: (*skbuff_vector) = NULL; mmsg_vector++; skbuff_vector++; The verify_header() < 0 path skips that via continue, so the freed skb is left in skbuff_vector[] and the cursors do not advance. The next iteration reads the same slot, gets the freed skb, and frees it again, producing a refcount underflow / use-after-free in the RX path. Discard the slot the same way the other paths do before continuing. Only transports whose verify_header() can return negative are affected: GRE and L2TPv3 do so on a cookie/session-id mismatch (raw/tap do not), so any peer on such a transport can trigger it without authentication.","publishedAt":"2026-08-15T13:17:52","lastModifiedAt":"2026-08-19T17:21:04","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74478","cvssScore":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","epssProbability":0.00573,"riskScore":1.03,"affectedProduct":"Linux kernel","affectedVersions":"unknown","vulnerabilityType":"Kernel","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-74478","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-74478","en":"https://www.redsauce.net/en/cves/CVE-2026-74478","fr":"https://www.redsauce.net/fr/cves/CVE-2026-74478","pt":"https://www.redsauce.net/pt/cves/CVE-2026-74478","de":"https://www.redsauce.net/de/cves/CVE-2026-74478","sk":"https://www.redsauce.net/sk/cves/CVE-2026-74478","el":"https://www.redsauce.net/el/cves/CVE-2026-74478"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-74478"}}