Answer in brief
CVE-2025-21648 records a Medium severity (CVSS 5.5) vulnerability in netfilter: conntrack: clamp maximum hashtable size to INT_MAX. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2025-21648 records a Medium severity (CVSS 5.5) vulnerability in netfilter: conntrack: clamp maximum hashtable size to INT_MAX. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (generic) and additional mapped packages. 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 5.5. 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), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <a965f7f0ea3ae61b9165bed619d5d6da02c75f80 || >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <b1b2353d768f1b80cd7fe045a70adee576b9b338 || >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <5552b4fd44be3393b930434a7845d8d95a2a3c33 || >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <d5807dd1328bbc86e059c5de80d1bbee9d58ca3d || >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <f559357d035877b9d0dcd273e0ff83e18e1d46aa || >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <b541ba7d1f5a5b7b3e2e22dc9e40e18a7d6dbc13 | a965f7f0ea3ae61b9165bed619d5d6da02c75f80, b1b2353d768f1b80cd7fe045a70adee576b9b338, 5552b4fd44be3393b930434a7845d8d95a2a3c33, d5807dd1328bbc86e059c5de80d1bbee9d58ca3d, f559357d035877b9d0dcd273e0ff83e18e1d46aa, b541ba7d1f5a5b7b3e2e22dc9e40e18a7d6dbc13 |
| Linux/Linuxgeneric | 4.7 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystemgeneric | >=0 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
Published upstream
Jan 19, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 14, 2026
In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: clamp maximum hashtable size to INT_MAX Use INT_MAX as maximum size for the conntrack hashtable. Otherwise, it is possible to hit WARN_ON_ONCE in __kvmalloc_node_noprof() when resizing hashtable because __GFP_NOWARN is unset. See: 0708a0afe291 ("mm: Consider __GFP_NOWARN flag for oversized kvmalloc() calls") Note: hashtable resize is only possible from init_netns.
Quoted source text, attributed separately from HOL analysis.
CVSS is 5.5. 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), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <a965f7f0ea3ae61b9165bed619d5d6da02c75f80 || >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <b1b2353d768f1b80cd7fe045a70adee576b9b338 || >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <5552b4fd44be3393b930434a7845d8d95a2a3c33 || >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <d5807dd1328bbc86e059c5de80d1bbee9d58ca3d || >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <f559357d035877b9d0dcd273e0ff83e18e1d46aa || >=9cc1c73ad66610bffc80b691136ffc1e9a3b1a58 <b541ba7d1f5a5b7b3e2e22dc9e40e18a7d6dbc13 | a965f7f0ea3ae61b9165bed619d5d6da02c75f80, b1b2353d768f1b80cd7fe045a70adee576b9b338, 5552b4fd44be3393b930434a7845d8d95a2a3c33, d5807dd1328bbc86e059c5de80d1bbee9d58ca3d, f559357d035877b9d0dcd273e0ff83e18e1d46aa, b541ba7d1f5a5b7b3e2e22dc9e40e18a7d6dbc13 |
| Linux/Linuxgeneric | 4.7 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystemgeneric | >=0 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
Published upstream
Jan 19, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 14, 2026
In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: clamp maximum hashtable size to INT_MAX Use INT_MAX as maximum size for the conntrack hashtable. Otherwise, it is possible to hit WARN_ON_ONCE in __kvmalloc_node_noprof() when resizing hashtable because __GFP_NOWARN is unset. See: 0708a0afe291 ("mm: Consider __GFP_NOWARN flag for oversized kvmalloc() calls") Note: hashtable resize is only possible from init_netns.
Quoted source text, attributed separately from HOL analysis.