Answer in brief
CVE-2025-21926 records a Medium severity (CVSS 5.5) vulnerability in net: gso: fix ownership in __udp_gso_segment. 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-2025-21926 records a Medium severity (CVSS 5.5) vulnerability in net: gso: fix ownership in __udp_gso_segment. 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 | >=ad405857b174ed31a97982bb129c320d03321cf5 <9f28205ddb76e86cac418332e952241d85fed0dc || >=ad405857b174ed31a97982bb129c320d03321cf5 <a2d1cca955ed34873e524cc2e6e885450d262f05 || >=ad405857b174ed31a97982bb129c320d03321cf5 <455217ac9db0cf9349b3933664355e907bb1a569 || >=ad405857b174ed31a97982bb129c320d03321cf5 <e8db70537878e1bb3fd83e5abcc6feefc0587828 || >=ad405857b174ed31a97982bb129c320d03321cf5 <01a83237644d6822bc7df2c5564fc81b0df84358 || >=ad405857b174ed31a97982bb129c320d03321cf5 <084819b0d8b1bd433b90142371eb9450d657f8ca || >=ad405857b174ed31a97982bb129c320d03321cf5 <c32da44cc9298eaa6109e3fc2c2b4e07cc4bf11b || >=ad405857b174ed31a97982bb129c320d03321cf5 <ee01b2f2d7d0010787c2343463965bbc283a497f | 9f28205ddb76e86cac418332e952241d85fed0dc, a2d1cca955ed34873e524cc2e6e885450d262f05, 455217ac9db0cf9349b3933664355e907bb1a569, e8db70537878e1bb3fd83e5abcc6feefc0587828, 01a83237644d6822bc7df2c5564fc81b0df84358, 084819b0d8b1bd433b90142371eb9450d657f8ca, c32da44cc9298eaa6109e3fc2c2b4e07cc4bf11b, ee01b2f2d7d0010787c2343463965bbc283a497f |
| Linux/Linuxgeneric | 4.18 | 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/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
Published upstream
Apr 1, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 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: gso: fix ownership in __udp_gso_segment In __udp_gso_segment the skb destructor is removed before segmenting the skb but the socket reference is kept as-is. This is an issue if the original skb is later orphaned as we can hit the following bug: kernel BUG at ./include/linux/skbuff.h:3312! (skb_orphan) RIP: 0010:ip_rcv_core+0x8b2/0xca0 Call Trace: ip_rcv+0xab/0x6e0 __netif_receive_skb_one_core+0x168/0x1b0 process_backlog+0x384/0x1100 __napi_poll.constprop.0+0xa1/0x370 net_rx_action+0x925/0xe50 The above can happen following a sequence of events when using OpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes an OVS_ACTION_ATTR_OUTPUT action: 1. OVS_ACTION_ATTR_USERSPACE is handled (in do_execute_actions): the skb goes through queue_gso_packets and then __udp_gso_segment, where its destructor is removed. 2. The segments' data are copied and sent to userspace. 3. OVS_ACTION_ATTR_OUTPUT is handled (in do_execute_actions) and the same original skb is sent to its path. 4. If it later hits skb_orphan, we hit the bug. Fix this by also removing the reference to the socket in __udp_gso_segment.
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 | >=ad405857b174ed31a97982bb129c320d03321cf5 <9f28205ddb76e86cac418332e952241d85fed0dc || >=ad405857b174ed31a97982bb129c320d03321cf5 <a2d1cca955ed34873e524cc2e6e885450d262f05 || >=ad405857b174ed31a97982bb129c320d03321cf5 <455217ac9db0cf9349b3933664355e907bb1a569 || >=ad405857b174ed31a97982bb129c320d03321cf5 <e8db70537878e1bb3fd83e5abcc6feefc0587828 || >=ad405857b174ed31a97982bb129c320d03321cf5 <01a83237644d6822bc7df2c5564fc81b0df84358 || >=ad405857b174ed31a97982bb129c320d03321cf5 <084819b0d8b1bd433b90142371eb9450d657f8ca || >=ad405857b174ed31a97982bb129c320d03321cf5 <c32da44cc9298eaa6109e3fc2c2b4e07cc4bf11b || >=ad405857b174ed31a97982bb129c320d03321cf5 <ee01b2f2d7d0010787c2343463965bbc283a497f | 9f28205ddb76e86cac418332e952241d85fed0dc, a2d1cca955ed34873e524cc2e6e885450d262f05, 455217ac9db0cf9349b3933664355e907bb1a569, e8db70537878e1bb3fd83e5abcc6feefc0587828, 01a83237644d6822bc7df2c5564fc81b0df84358, 084819b0d8b1bd433b90142371eb9450d657f8ca, c32da44cc9298eaa6109e3fc2c2b4e07cc4bf11b, ee01b2f2d7d0010787c2343463965bbc283a497f |
| Linux/Linuxgeneric | 4.18 | 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/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
Published upstream
Apr 1, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 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: gso: fix ownership in __udp_gso_segment In __udp_gso_segment the skb destructor is removed before segmenting the skb but the socket reference is kept as-is. This is an issue if the original skb is later orphaned as we can hit the following bug: kernel BUG at ./include/linux/skbuff.h:3312! (skb_orphan) RIP: 0010:ip_rcv_core+0x8b2/0xca0 Call Trace: ip_rcv+0xab/0x6e0 __netif_receive_skb_one_core+0x168/0x1b0 process_backlog+0x384/0x1100 __napi_poll.constprop.0+0xa1/0x370 net_rx_action+0x925/0xe50 The above can happen following a sequence of events when using OpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes an OVS_ACTION_ATTR_OUTPUT action: 1. OVS_ACTION_ATTR_USERSPACE is handled (in do_execute_actions): the skb goes through queue_gso_packets and then __udp_gso_segment, where its destructor is removed. 2. The segments' data are copied and sent to userspace. 3. OVS_ACTION_ATTR_OUTPUT is handled (in do_execute_actions) and the same original skb is sent to its path. 4. If it later hits skb_orphan, we hit the bug. Fix this by also removing the reference to the socket in __udp_gso_segment.
Quoted source text, attributed separately from HOL analysis.