https://cve.radiocsirt.org Contains only the most 10 recent entries. http://www.rssboard.org/rss-specification python-feedgen en Tue, 06 Oct 2026 23:25:23 +0000 https://cve.radiocsirt.org/vuln/cve-2021-47546 <p><strong>Affected:</strong> Linux</p> <p>In the Linux kernel, the following vulnerability has been resolved:</p> <p>ipv6: fix memory leak in fib6_rule_suppress</p> <p>The kernel leaks memory when a `fib` rule is present in IPv6 nftables firewall rules and a suppress_prefix rule is present in the IPv6 routing rules (used by certain tools such as wg-quick). In such scenarios, every incoming packet will leak an allocation in `ip6_dst_cache` slab cache.</p> <p>After some hours of `bpftrace`-ing and source code reading, I tracked down the issue to ca7a03c41753 (&#34;ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule&#34;).</p> <p>The problem with that change is that the generic `args-&gt;flags` always have `FIB_LOOKUP_NOREF` set[1][2] but the IPv6-specific flag `RT6_LOOKUP_F_DST_NOREF` might not be, leading to `fib6_rule_suppress` not decreasing the refcount when needed.</p> <p>How to reproduce: - Add the following nftables rule to a prerouting chain: meta nfproto ipv6 fib saddr . mark . iif oif missing drop This can be done with: sudo nft create table inet test sudo nft create chain inet test test_chain &#39;{ type filter hook prerouting priority filter + 10; policy accept; }&#39; sudo nft add rule inet test test_chain meta nfproto ipv6 fib saddr . mark . iif oif missing drop - Run: sudo ip -6 rule add table main suppress_prefixlength 0 - Watch `sudo slabtop -o | grep ip6_dst_cache` to see memory usage increase with every incoming ipv6 packet.</p> <p>This patch exposes the protocol-specific flags to the protocol specific `sup…</p> <p><strong>Affected:</strong> Linux</p> <p>In the Linux kernel, the following vulnerability has been resolved:</p> <p>ipv6: fix memory leak in fib6_rule_suppress</p> <p>The kernel leaks memory when a `fib` rule is present in IPv6 nftables firewall rules and a suppress_prefix rule is present in the IPv6 routing rules (used by certain tools such as wg-quick). In such scenarios, every incoming packet will leak an allocation in `ip6_dst_cache` slab cache.</p> <p>After some hours of `bpftrace`-ing and source code reading, I tracked down the issue to ca7a03c41753 (&#34;ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule&#34;).</p> <p>The problem with that change is that the generic `args-&gt;flags` always have `FIB_LOOKUP_NOREF` set[1][2] but the IPv6-specific flag `RT6_LOOKUP_F_DST_NOREF` might not be, leading to `fib6_rule_suppress` not decreasing the refcount when needed.</p> <p>How to reproduce: - Add the following nftables rule to a prerouting chain: meta nfproto ipv6 fib saddr . mark . iif oif missing drop This can be done with: sudo nft create table inet test sudo nft create chain inet test test_chain &#39;{ type filter hook prerouting priority filter + 10; policy accept; }&#39; sudo nft add rule inet test test_chain meta nfproto ipv6 fib saddr . mark . iif oif missing drop - Run: sudo ip -6 rule add table main suppress_prefixlength 0 - Watch `sudo slabtop -o | grep ip6_dst_cache` to see memory usage increase with every incoming ipv6 packet.</p> <p>This patch exposes the protocol-specific flags to the protocol specific `sup…</p> https://cve.radiocsirt.org/vuln/cve-2021-47546