{"cve":"CVE-2025-68813","nvd":{"published":"2026-01-13T16:16:03.523","modified":"2026-10-19T19:17:06.470","status":"Deferred","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: fix ipv4 null-ptr-deref in route error path\n\nThe IPv4 code path in __ip_vs_get_out_rt() calls dst_link_failure()\nwithout ensuring skb->dev is set, leading to a NULL pointer dereference\nin fib_compute_spec_dst() when ipv4_link_failure() attempts to send\nICMP destination unreachable messages.\n\nThe issue emerged after commit ed0de45a1008 (\"ipv4: recompile ip options\nin ipv4_link_failure\") started calling __ip_options_compile() from\nipv4_link_failure(). This code path eventually calls fib_compute_spec_dst()\nwhich dereferences skb->dev. An attempt was made to fix the NULL skb->dev\ndereference in commit 0113d9c9d1cc (\"ipv4: fix null-deref in\nipv4_link_failure\"), but it only addressed the immediate dev_net(skb->dev)\ndereference by using a fallback device. The fix was incomplete because\nfib_compute_spec_dst() later in the call chain still accesses skb->dev\ndirectly, which remains NULL when IPVS calls dst_link_failure().\n\nThe crash occurs when:\n1. IPVS processes a packet in NAT mode with a misconfigured destination\n2. Route lookup fails in __ip_vs_get_out_rt() before establishing a route\n3. The error path calls dst_link_failure(skb) with skb->dev == NULL\n4. ipv4_link_failure() → ipv4_send_dest_unreach() →\n   __ip_options_compile() → fib_compute_spec_dst()\n5. fib_compute_spec_dst() dereferences NULL skb->dev\n\nApply the same fix used for IPv6 in commit 326bf17ea5d4 (\"ipvs: fix\nipv6 route unreach panic\"): set skb->dev from skb_dst(skb)->dev before\ncalling dst_link_failure().\n\nKASAN: null-ptr-deref in range [0x0000000000000328-0x000000000000032f]\nCPU: 1 PID: 12732 Comm: syz.1.3469 Not tainted 6.6.114 #2\nRIP: 0010:__in_dev_get_rcu include/linux/inetdevice.h:233\nRIP: 0010:fib_compute_spec_dst+0x17a/0x9f0 net/ipv4/fib_frontend.c:285\nCall Trace:\n  <TASK>\n  spec_dst_fill net/ipv4/ip_options.c:232\n  spec_dst_fill net/ipv4/ip_options.c:229\n  __ip_options_compile+0x13a1/0x17d0 net/ipv4/ip_options.c:330\n  ipv4_send_dest_unreach net/ipv4/route.c:1252\n  ipv4_link_failure+0x702/0xb80 net/ipv4/route.c:1265\n  dst_link_failure include/net/dst.h:437\n  __ip_vs_get_out_rt+0x15fd/0x19e0 net/netfilter/ipvs/ip_vs_xmit.c:412\n  ip_vs_nat_xmit+0x1d8/0xc80 net/netfilter/ipvs/ip_vs_xmit.c:764","cvss_v4":null,"cvss_v3":null,"cwes":["CWE-476"],"references":["https://git.kernel.org/stable/c/25ab24df31f7af843c96a38e0781b9165216e1a8","https://git.kernel.org/stable/c/312d7cd88882fc6cadcc08b02287497aaaf94bcd","https://git.kernel.org/stable/c/4729ff0581fbb7ad098b6153b76b6f5aac94618a","https://git.kernel.org/stable/c/689a627d14788ad772e0fa24c2e57a23dbc7ce90","https://git.kernel.org/stable/c/ad891bb3d079a46a821bf2b8867854645191bab0"],"products":[],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-68813","score":0.00207,"percentile":0.10747,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}