# CVE-2021-47146: linux: In the Linux kernel, the following vulnerability has been resolved:  mld: fix panic in mld_newpack()  mld_newpack() d...

CVE-2021-47146 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47146, released March 25, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-47146
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0024
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 25, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  mld: fix panic in mld_newpack()  mld_newpack() doesn't allow to allocate high order page, only order-0 allocation is allowed. If headroom size is too large, a kernel panic could occur in skb_put().  Test commands:     ip netns del A     ip netns del B     ip netns add A     ip netns add B     ip link add veth0 type veth peer name veth1     ip link set veth0 netns A     ip link set veth1 netns B      ip netns exec A ip link set lo up     ip netns exec A ip link set veth0 up     ip netns exec A ip -6 a a 2001:db8:0::1/64 dev veth0     ip netns exec B ip link set lo up     ip netns exec B ip link set veth1 up     ip netns exec B ip -6 a a 2001:db8:0::2/64 dev veth1     for i in {1..99}     do         let A=$i-1         ip netns exec A ip link add ip6gre$i type ip6gre \ 	local 2001:db8:$A::1 remote 2001:db8:$A::2 encaplimit 100         ip netns exec A ip -6 a a 2001:db8:$i::1/64 dev ip6gre$i         ip netns exec A ip link set ip6gre$i up          ip netns exec B ip link add ip6gre$i type ip6gre \ 	local 2001:db8:$A::2 remote 2001:db8:$A::1 encaplimit 100         ip netns exec B ip -6 a a 2001:db8:$i::2/64 dev ip6gre$i         ip netns exec B ip link set ip6gre$i up     done  Splat looks like: kernel BUG at net/core/skbuff.c:110! invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.12.0+ #891 Workqueue: ipv6_addrconf addrconf_dad_work RIP: 0010:skb_panic+0x15d/0x15f Code: 92 fe 4c 8b 4c 24 10 53 8b 4d 70 45 89 e0 48 c7 c7 00 ae 79 83 41 57 41 56 41 55 48 8b 54 24 a6 26 f9 ff <0f> 0b 48 8b 6c 24 20 89 34 24 e8 4a 4e 92 fe 8b 34 24 48 c7 c1 20 RSP: 0018:ffff88810091f820 EFLAGS: 00010282 RAX: 0000000000000089 RBX: ffff8881086e9000 RCX: 0000000000000000 RDX: 0000000000000089 RSI: 0000000000000008 RDI: ffffed1020123efb RBP: ffff888005f6eac0 R08: ffffed1022fc0031 R09: ffffed1022fc0031 R10: ffff888117e00187 R11: ffffed1022fc0030 R12: 0000000000000028 R13: ffff888008284eb0 R14: 0000000000000ed8 R15: 0000000000000ec0 FS:  0000000000000000(0000) GS:ffff888117c00000(0000) knlGS:0000000000000000 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8b801c5640 CR3: 0000000033c2c006 CR4: 00000000003706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace:  ? ip6_mc_hdr.isra.26.constprop.46+0x12a/0x600  ? ip6_mc_hdr.isra.26.constprop.46+0x12a/0x600  skb_put.cold.104+0x22/0x22  ip6_mc_hdr.isra.26.constprop.46+0x12a/0x600  ? rcu_read_lock_sched_held+0x91/0xc0  mld_newpack+0x398/0x8f0  ? ip6_mc_hdr.isra.26.constprop.46+0x600/0x600  ? lock_contended+0xc40/0xc40  add_grhead.isra.33+0x280/0x380  add_grec+0x5ca/0xff0  ? mld_sendpack+0xf40/0xf40  ? lock_downgrade+0x690/0x690  mld_send_initial_cr.part.34+0xb9/0x180  ipv6_mc_dad_complete+0x15d/0x1b0  addrconf_dad_completed+0x8d2/0xbb0  ? lock_downgrade+0x690/0x690  ? addrconf_rs_timer+0x660/0x660  ? addrconf_dad_work+0x73c/0x10e0  addrconf_dad_work+0x73c/0x10e0  Allowing high order page allocation could fix this problem.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.14.6-1 | [DEBIAN-CVE-2021-47146](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47146.md) | Mar 25, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.14.6-1 | [DEBIAN-CVE-2021-47146](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47146.md) | Mar 25, 2024 |
| Linux | linux Debian 14 | 5.14.6-1 | [DEBIAN-CVE-2021-47146](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47146.md) | Mar 25, 2024 |

---

Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.