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NVD / CVE Program· CNA Linux

CVE-2021-47146: mld: fix panic in mld_newpack()

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.23% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 020ef930b826d21c5446fdc9db80fd72a791bc21, 0e35b7457b7b6e73ffeaaca1a577fdf1af0feca1, 17728616a4c85baf0edc975c60ba4e4157684d9a.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 020ef930b826d21c5446fdc9db80fd72a791bc21, 0e35b7457b7b6e73ffeaaca1a577fdf1af0feca1, 17728616a4c85baf0edc975c60ba4e4157684d9a or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Mar 25, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 14th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-47146

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel2.6.35 and later · before 4.4.271
  • linux linux kernel4.5 and later · before 4.9.271
  • linux linux kernel4.10 and later · before 4.14.235
  • linux linux kernel4.15 and later · before 4.19.193
  • linux linux kernel4.20 and later · before 5.4.124
  • linux linux kernel5.5 and later · before 5.10.42
  • linux linux kernel5.11 and later · before 5.12.9
  • linux linux kernel5.13

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2.6.35affected
    • 72e09ad107e78d69ff4d3b97a69f0aad2b77280f and later · before 0e35b7457b7b6e73ffeaaca1a577fdf1af0feca1affected · git
    • 72e09ad107e78d69ff4d3b97a69f0aad2b77280f and later · before 17728616a4c85baf0edc975c60ba4e4157684d9aaffected · git
    • 72e09ad107e78d69ff4d3b97a69f0aad2b77280f and later · before 221142038f36d9f28b64e83e954774da4d4ccd17affected · git
    • 72e09ad107e78d69ff4d3b97a69f0aad2b77280f and later · before 4b77ad9097067b31237eeeee0bf70f80849680a0affected · git
    • 72e09ad107e78d69ff4d3b97a69f0aad2b77280f and later · before 37d697759958d111439080bab7e14d2b0e7b39f5affected · git
    • 72e09ad107e78d69ff4d3b97a69f0aad2b77280f and later · before beb39adb150f8f3b516ddf7c39835a9788704d23affected · git
    • 72e09ad107e78d69ff4d3b97a69f0aad2b77280f and later · before a76fb9ba545289379acf409653ad5f74417be59caffected · git
    • 72e09ad107e78d69ff4d3b97a69f0aad2b77280f and later · before 020ef930b826d21c5446fdc9db80fd72a791bc21affected · git
    • before 2.6.35not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.14.6-15.14.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-47143Mar 25, 2024 · net/smc: remove device from smcd_dev_list after failed device_add()
    22Monitor
  • ← EarlierCVE-2021-47145Mar 25, 2024 · btrfs: do not BUG_ON in link_to_fixup_dir
    22Monitor
  • Later →CVE-2021-47147Mar 25, 2024 · ptp: ocp: Fix a resource leak in an error handling path
    24Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux020ef930b826d21c5446fdc9db80fd72a791bc21Vendor (CNA)
Linux Linux0e35b7457b7b6e73ffeaaca1a577fdf1af0feca1Vendor (CNA)
Linux Linux17728616a4c85baf0edc975c60ba4e4157684d9aVendor (CNA)
Linux Linux221142038f36d9f28b64e83e954774da4d4ccd17Vendor (CNA)
Linux Linux37d697759958d111439080bab7e14d2b0e7b39f5Vendor (CNA)
Linux Linux4b77ad9097067b31237eeeee0bf70f80849680a0Vendor (CNA)
Linux Linuxa76fb9ba545289379acf409653ad5f74417be59cVendor (CNA)
Linux Linuxbeb39adb150f8f3b516ddf7c39835a9788704d23Vendor (CNA)
debian:linux5.14.6-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records