Answer in brief
CVE-2026-43011 records a Critical severity (CVSS 9.8) vulnerability in net/x25: Fix potential double free of skb. 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 1518-4 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 9.8. 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 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5d0aa038a90b30c9bedde0c41c1fdcd98ecb16e9 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3f5e3005984645bf5bd129c6b13149879580b1fb || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f782dd382203b2a8c4552a628431b7de65a19a7b || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <143d4fa68ae9efb83b0c55b12cc7f0d03732a2b1 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <524371398d8463ea7e101fce2cbf3915645d1730 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fa1dbc93530b34fab0da9862426fe9c918c74dc0 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c87dd137c0dad07cc55f98181ff380b0c23d2878 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d10a26aa4d072320530e6968ef945c8c575edf61 | 5d0aa038a90b30c9bedde0c41c1fdcd98ecb16e9, 3f5e3005984645bf5bd129c6b13149879580b1fb, f782dd382203b2a8c4552a628431b7de65a19a7b, 143d4fa68ae9efb83b0c55b12cc7f0d03732a2b1, 524371398d8463ea7e101fce2cbf3915645d1730, fa1dbc93530b34fab0da9862426fe9c918c74dc0, c87dd137c0dad07cc55f98181ff380b0c23d2878, d10a26aa4d072320530e6968ef945c8c575edf61 |
| Linux/Linuxgeneric | 2.6.12 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
Published upstream
May 1, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 8, 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: net/x25: Fix potential double free of skb When alloc_skb fails in x25_queue_rx_frame it calls kfree_skb(skb) at line 48 and returns 1 (error). This error propagates back through the call chain: x25_queue_rx_frame returns 1 | v x25_state3_machine receives the return value 1 and takes the else branch at line 278, setting queued=0 and returning 0 | v x25_process_rx_frame returns queued=0 | v x25_backlog_rcv at line 452 sees queued=0 and calls kfree_skb(skb) again This would free the same skb twice. Looking at x25_backlog_rcv: net/x25/x25_in.c:x25_backlog_rcv() { ... queued = x25_process_rx_frame(sk, skb); ... if (!queued) kfree_skb(skb); }
Quoted source text, attributed separately from HOL analysis.