Answer in brief
CVE-2021-47109 records a High severity (CVSS 7.5) vulnerability in neighbour: allow NUD_NOARP entries to be forced GCed. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc6:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | 5.0 | Not reported |
| Linux/Linuxgeneric | >=58956317c8de52009d1a38a721474c24aef74fe7 <d99029e6aab62aef0a0251588b2867e77e83b137 || >=58956317c8de52009d1a38a721474c24aef74fe7 <d17d47da59f726dc4c87caebda3a50333d7e2fd3 || >=58956317c8de52009d1a38a721474c24aef74fe7 <ddf088d7aaaaacfc836104f2e632b29b1d383cfc || >=58956317c8de52009d1a38a721474c24aef74fe7 <7a6b1ab7475fd6478eeaf5c9d1163e7a18125c8f | d99029e6aab62aef0a0251588b2867e77e83b137, d17d47da59f726dc4c87caebda3a50333d7e2fd3, ddf088d7aaaaacfc836104f2e632b29b1d383cfc, 7a6b1ab7475fd6478eeaf5c9d1163e7a18125c8f |
Published upstream
Mar 15, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 4, 2026
In the Linux kernel, the following vulnerability has been resolved: neighbour: allow NUD_NOARP entries to be forced GCed IFF_POINTOPOINT interfaces use NUD_NOARP entries for IPv6. It's possible to fill up the neighbour table with enough entries that it will overflow for valid connections after that. This behaviour is more prevalent after commit 58956317c8de ("neighbor: Improve garbage collection") is applied, as it prevents removal from entries that are not NUD_FAILED, unless they are more than 5s old.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2021-47109 records a High severity (CVSS 7.5) vulnerability in neighbour: allow NUD_NOARP entries to be forced GCed. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc6:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | 5.0 | Not reported |
| Linux/Linuxgeneric | >=58956317c8de52009d1a38a721474c24aef74fe7 <d99029e6aab62aef0a0251588b2867e77e83b137 || >=58956317c8de52009d1a38a721474c24aef74fe7 <d17d47da59f726dc4c87caebda3a50333d7e2fd3 || >=58956317c8de52009d1a38a721474c24aef74fe7 <ddf088d7aaaaacfc836104f2e632b29b1d383cfc || >=58956317c8de52009d1a38a721474c24aef74fe7 <7a6b1ab7475fd6478eeaf5c9d1163e7a18125c8f | d99029e6aab62aef0a0251588b2867e77e83b137, d17d47da59f726dc4c87caebda3a50333d7e2fd3, ddf088d7aaaaacfc836104f2e632b29b1d383cfc, 7a6b1ab7475fd6478eeaf5c9d1163e7a18125c8f |
Published upstream
Mar 15, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 4, 2026
In the Linux kernel, the following vulnerability has been resolved: neighbour: allow NUD_NOARP entries to be forced GCed IFF_POINTOPOINT interfaces use NUD_NOARP entries for IPv6. It's possible to fill up the neighbour table with enough entries that it will overflow for valid connections after that. This behaviour is more prevalent after commit 58956317c8de ("neighbor: Improve garbage collection") is applied, as it prevents removal from entries that are not NUD_FAILED, unless they are more than 5s old.
Quoted source text, attributed separately from HOL analysis.