FKIE_CVE-2025-68813

Vulnerability from fkie_nvd - Published: 2026-01-13 16:16 - Updated: 2026-01-19 13:16
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ipvs: fix ipv4 null-ptr-deref in route error path The IPv4 code path in __ip_vs_get_out_rt() calls dst_link_failure() without ensuring skb->dev is set, leading to a NULL pointer dereference in fib_compute_spec_dst() when ipv4_link_failure() attempts to send ICMP destination unreachable messages. The issue emerged after commit ed0de45a1008 ("ipv4: recompile ip options in ipv4_link_failure") started calling __ip_options_compile() from ipv4_link_failure(). This code path eventually calls fib_compute_spec_dst() which dereferences skb->dev. An attempt was made to fix the NULL skb->dev dereference in commit 0113d9c9d1cc ("ipv4: fix null-deref in ipv4_link_failure"), but it only addressed the immediate dev_net(skb->dev) dereference by using a fallback device. The fix was incomplete because fib_compute_spec_dst() later in the call chain still accesses skb->dev directly, which remains NULL when IPVS calls dst_link_failure(). The crash occurs when: 1. IPVS processes a packet in NAT mode with a misconfigured destination 2. Route lookup fails in __ip_vs_get_out_rt() before establishing a route 3. The error path calls dst_link_failure(skb) with skb->dev == NULL 4. ipv4_link_failure() → ipv4_send_dest_unreach() → __ip_options_compile() → fib_compute_spec_dst() 5. fib_compute_spec_dst() dereferences NULL skb->dev Apply the same fix used for IPv6 in commit 326bf17ea5d4 ("ipvs: fix ipv6 route unreach panic"): set skb->dev from skb_dst(skb)->dev before calling dst_link_failure(). KASAN: null-ptr-deref in range [0x0000000000000328-0x000000000000032f] CPU: 1 PID: 12732 Comm: syz.1.3469 Not tainted 6.6.114 #2 RIP: 0010:__in_dev_get_rcu include/linux/inetdevice.h:233 RIP: 0010:fib_compute_spec_dst+0x17a/0x9f0 net/ipv4/fib_frontend.c:285 Call Trace: <TASK> spec_dst_fill net/ipv4/ip_options.c:232 spec_dst_fill net/ipv4/ip_options.c:229 __ip_options_compile+0x13a1/0x17d0 net/ipv4/ip_options.c:330 ipv4_send_dest_unreach net/ipv4/route.c:1252 ipv4_link_failure+0x702/0xb80 net/ipv4/route.c:1265 dst_link_failure include/net/dst.h:437 __ip_vs_get_out_rt+0x15fd/0x19e0 net/netfilter/ipvs/ip_vs_xmit.c:412 ip_vs_nat_xmit+0x1d8/0xc80 net/netfilter/ipvs/ip_vs_xmit.c:764
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/25ab24df31f7af843c96a38e0781b9165216e1a8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/312d7cd88882fc6cadcc08b02287497aaaf94bcd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4729ff0581fbb7ad098b6153b76b6f5aac94618a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/689a627d14788ad772e0fa24c2e57a23dbc7ce90
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ad891bb3d079a46a821bf2b8867854645191bab0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cdeff10851c37a002d87a035818ebd60fdb74447
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dd72a93c80408f06327dd2d956eb1a656d0b5903
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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-\u003edev 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-\u003edev. An attempt was made to fix the NULL skb-\u003edev\ndereference in commit 0113d9c9d1cc (\"ipv4: fix null-deref in\nipv4_link_failure\"), but it only addressed the immediate dev_net(skb-\u003edev)\ndereference by using a fallback device. The fix was incomplete because\nfib_compute_spec_dst() later in the call chain still accesses skb-\u003edev\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-\u003edev == NULL\n4. ipv4_link_failure() \u2192 ipv4_send_dest_unreach() \u2192\n   __ip_options_compile() \u2192 fib_compute_spec_dst()\n5. fib_compute_spec_dst() dereferences NULL skb-\u003edev\n\nApply the same fix used for IPv6 in commit 326bf17ea5d4 (\"ipvs: fix\nipv6 route unreach panic\"): set skb-\u003edev from skb_dst(skb)-\u003edev 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  \u003cTASK\u003e\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"
    }
  ],
  "id": "CVE-2025-68813",
  "lastModified": "2026-01-19T13:16:14.950",
  "metrics": {},
  "published": "2026-01-13T16:16:03.523",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/25ab24df31f7af843c96a38e0781b9165216e1a8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/312d7cd88882fc6cadcc08b02287497aaaf94bcd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4729ff0581fbb7ad098b6153b76b6f5aac94618a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/689a627d14788ad772e0fa24c2e57a23dbc7ce90"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ad891bb3d079a46a821bf2b8867854645191bab0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cdeff10851c37a002d87a035818ebd60fdb74447"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dd72a93c80408f06327dd2d956eb1a656d0b5903"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.