CVE-2021-47309: net: validate lwtstate->data before returning from skb_tunnel_info()
Noroxi assessment
Priority: Monitor (action score 28/100)
- 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: 0.25% (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 2179d96ec702cc33ead02a9ce40ece599b8538c5, 67a9c94317402b826fc3db32afc8f39336803d97, 83bdcfbd968bcc91a0632b7b625e4a9b0cba5e0d.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to Linux Linux 2179d96ec702cc33ead02a9ce40ece599b8538c5, 67a9c94317402b826fc3db32afc8f39336803d97, 83bdcfbd968bcc91a0632b7b625e4a9b0cba5e0d 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: net: validate lwtstate->data before returning from skb_tunnel_info() skb_tunnel_info() returns pointer of lwtstate->data as ip_tunnel_info type without validation. lwtstate->data can have various types such as mpls_iptunnel_encap, etc and these are not compatible. So skb_tunnel_info() should validate before returning that pointer. Splat looks like: BUG: KASAN: slab-out-of-bounds in vxlan_get_route+0x418/0x4b0 [vxlan] Read of size 2 at addr ffff888106ec2698 by task ping/811 CPU: 1 PID: 811 Comm: ping Not tainted 5.13.0+ #1195 Call Trace: dump_stack_lvl+0x56/0x7b print_address_description.constprop.8.cold.13+0x13/0x2ee ? vxlan_get_route+0x418/0x4b0 [vxlan] ? vxlan_get_route+0x418/0x4b0 [vxlan] kasan_report.cold.14+0x83/0xdf ? vxlan_get_route+0x418/0x4b0 [vxlan] vxlan_get_route+0x418/0x4b0 [vxlan] [ ... ] vxlan_xmit_one+0x148b/0x32b0 [vxlan] [ ... ] vxlan_xmit+0x25c5/0x4780 [vxlan] [ ... ] dev_hard_start_xmit+0x1ae/0x6e0 __dev_queue_xmit+0x1f39/0x31a0 [ ... ] neigh_xmit+0x2f9/0x940 mpls_xmit+0x911/0x1600 [mpls_iptunnel] lwtunnel_xmit+0x18f/0x450 ip_finish_output2+0x867/0x2040 [ ... ]
- Published
- May 21, 2024
- Updated
- Aug 5, 2026
- EPSS
- 0.2% · 16th percentile
- CWE
- CWE-125
Report tools
Action score
28
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.1 / 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.
CNA vs NVD score
- NVD
- 7.1
- CNA · Linux
- 7.8
- 0.7 point gap
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
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.
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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.
We use this product, ask for helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- linux linux kernel4.3 and later · before 4.4.277
- linux linux kernel4.5 and later · before 4.9.277
- linux linux kernel4.10 and later · before 4.14.241
- linux linux kernel4.15 and later · before 4.19.199
- linux linux kernel4.20 and later · before 5.4.135
- linux linux kernel5.5 and later · before 5.10.53
- linux linux kernel5.11 and later · before 5.13.5
- linux linux kernel5.14
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
- 4.3affected
- 61adedf3e3f1d3f032c5a6a299978d91eff6d555 and later · before e7f3c9df40515a6c6b46f36c4c94cf48a043f887affected · git
- 61adedf3e3f1d3f032c5a6a299978d91eff6d555 and later · before b61d327cd3cc5ea591f3bf751dd11e034f388bb5affected · git
- 61adedf3e3f1d3f032c5a6a299978d91eff6d555 and later · before 83bdcfbd968bcc91a0632b7b625e4a9b0cba5e0daffected · git
- 61adedf3e3f1d3f032c5a6a299978d91eff6d555 and later · before 8bb1589c89e61e3b182dd546f1021928ebb5c2a6affected · git
- 61adedf3e3f1d3f032c5a6a299978d91eff6d555 and later · before 8aa13a86964cdec4fd969ef677c6614ff068641aaffected · git
- 61adedf3e3f1d3f032c5a6a299978d91eff6d555 and later · before 2179d96ec702cc33ead02a9ce40ece599b8538c5affected · git
- 61adedf3e3f1d3f032c5a6a299978d91eff6d555 and later · before a915379594f1e045421635c6316d8f3ffa018c58affected · git
- 61adedf3e3f1d3f032c5a6a299978d91eff6d555 and later · before 67a9c94317402b826fc3db32afc8f39336803d97affected · git
- before 4.3not affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 5.14.6-1 | 5.14.6-1 |
| SUSE:Linux Enterprise High Availability Extension 12 SP5 | kernel-default | before 4.12.14-122.222.1 | 4.12.14-122.222.1 |
| SUSE:Linux Enterprise Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_58 | before 1-8.3.1 | 1-8.3.1 |
| SUSE:Linux Enterprise Real Time 12 SP5 | kernel-rt | before 4.12.14-10.191.1 | 4.12.14-10.191.1 |
| SUSE:Linux Enterprise Real Time 12 SP5 | kernel-rt_debug | before 4.12.14-10.191.1 | 4.12.14-10.191.1 |
| SUSE:Linux Enterprise Real Time 12 SP5 | kernel-source-rt | before 4.12.14-10.191.1 | 4.12.14-10.191.1 |
| SUSE:Linux Enterprise Real Time 12 SP5 | kernel-syms-rt | before 4.12.14-10.191.1 | 4.12.14-10.191.1 |
| SUSE:Linux Enterprise Server 12 SP5 | kernel-azure | before 4.12.14-16.191.1 | 4.12.14-16.191.1 |
| SUSE:Linux Enterprise Server 12 SP5 | kernel-source | before 4.12.14-122.222.1 | 4.12.14-122.222.1 |
| SUSE:Linux Enterprise Server 12 SP5 | kernel-source-azure | before 4.12.14-16.191.1 | 4.12.14-16.191.1 |
| SUSE:Linux Enterprise Server 12 SP5 | kernel-syms | before 4.12.14-122.222.1 | 4.12.14-122.222.1 |
| SUSE:Linux Enterprise Server 12 SP5 | kernel-syms-azure | before 4.12.14-16.191.1 | 4.12.14-16.191.1 |
| SUSE:Linux Enterprise Software Development Kit 12 SP5 | kernel-docs | before 4.12.14-122.222.1 | 4.12.14-122.222.1 |
| SUSE:Linux Enterprise Software Development Kit 12 SP5 | kernel-obs-build | before 4.12.14-122.222.1 | 4.12.14-122.222.1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV90Now
- 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 KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
Published before and after this one in the same product
- ← EarlierCVE-2021-47307May 21, 2024 · cifs: prevent NULL deref in cifs_compose_mount_options()22Monitor
- ← EarlierCVE-2021-47308May 21, 2024 · scsi: libfc: Fix array index out of bound exception35Monitor
- Later →CVE-2021-47310May 21, 2024 · net: ti: fix UAF in tlan_remove_one31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 2179d96ec702cc33ead02a9ce40ece599b8538c5 | Vendor (CNA) |
| Linux Linux | 67a9c94317402b826fc3db32afc8f39336803d97 | Vendor (CNA) |
| Linux Linux | 83bdcfbd968bcc91a0632b7b625e4a9b0cba5e0d | Vendor (CNA) |
| Linux Linux | 8aa13a86964cdec4fd969ef677c6614ff068641a | Vendor (CNA) |
| Linux Linux | 8bb1589c89e61e3b182dd546f1021928ebb5c2a6 | Vendor (CNA) |
| Linux Linux | a915379594f1e045421635c6316d8f3ffa018c58 | Vendor (CNA) |
| Linux Linux | b61d327cd3cc5ea591f3bf751dd11e034f388bb5 | Vendor (CNA) |
| Linux Linux | e7f3c9df40515a6c6b46f36c4c94cf48a043f887 | Vendor (CNA) |
| debian:linux | 5.14.6-1 · Debian:12 | Package registry (OSV) |
| suse:kernel-azure | 4.12.14-16.191.1 · SUSE:Linux Enterprise Server 12 SP5 | Package registry (OSV) |
| suse:kernel-default | 4.12.14-122.222.1 · SUSE:Linux Enterprise High Availability Extension 12 SP5 | Package registry (OSV) |
| suse:kernel-docs | 4.12.14-122.222.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5 | Package registry (OSV) |
| suse:kernel-obs-build | 4.12.14-122.222.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5 | Package registry (OSV) |
| suse:kernel-rt | 4.12.14-10.191.1 · SUSE:Linux Enterprise Real Time 12 SP5 | Package registry (OSV) |
| suse:kernel-rt_debug | 4.12.14-10.191.1 · SUSE:Linux Enterprise Real Time 12 SP5 | Package registry (OSV) |
| suse:kernel-source | 4.12.14-122.222.1 · SUSE:Linux Enterprise Server 12 SP5 | Package registry (OSV) |
| suse:kernel-source-azure | 4.12.14-16.191.1 · SUSE:Linux Enterprise Server 12 SP5 | Package registry (OSV) |
| suse:kernel-source-rt | 4.12.14-10.191.1 · SUSE:Linux Enterprise Real Time 12 SP5 | Package registry (OSV) |
| suse:kernel-syms-azure | 4.12.14-16.191.1 · SUSE:Linux Enterprise Server 12 SP5 | Package registry (OSV) |
| suse:kernel-syms-rt | 4.12.14-10.191.1 · SUSE:Linux Enterprise Real Time 12 SP5 | Package registry (OSV) |
| suse:kgraft-patch-SLE12-SP5_Update_58 | 1-8.3.1 · SUSE:Linux Enterprise Live Patching 12 SP5 | Package 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 researchersFinders, 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.
- TR-24-0519 · May 22, 2024(Linux Kernel Güncellemesi)
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
- high · data can be read
- 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
- High
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-125 · Out-of-bounds ReadCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (7 more)Show less
- git.kernel.org/stable/c/67a9c94317402b826fc3db32afc8f39336803d97
- git.kernel.org/stable/c/83bdcfbd968bcc91a0632b7b625e4a9b0cba5e0d
- git.kernel.org/stable/c/8aa13a86964cdec4fd969ef677c6614ff068641a
- git.kernel.org/stable/c/8bb1589c89e61e3b182dd546f1021928ebb5c2a6
- git.kernel.org/stable/c/a915379594f1e045421635c6316d8f3ffa018c58
- git.kernel.org/stable/c/b61d327cd3cc5ea591f3bf751dd11e034f388bb5
- git.kernel.org/stable/c/e7f3c9df40515a6c6b46f36c4c94cf48a043f887
Vendor advisories and official records. Exploit/PoC links are deliberately left out.