CVE-2025-21926
What it is
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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 7.8 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Record status
- Modified
Affected
- Linux Kernel < 5.4.291
- Linux Kernel < 5.10.235
- Linux Kernel < 5.15.179
- Linux Kernel < 6.1.131
- Linux Kernel < 6.6.83
- Linux Kernel < 6.12.19
- Linux Kernel < 6.13.7
- Linux Kernel 6.14
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-21926.md and follow it. Check whether this project is affected by CVE-2025-21926. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/01a83237644d6822bc7df2c5564fc81b0df84358
- https://git.kernel.org/stable/c/084819b0d8b1bd433b90142371eb9450d657f8ca
- https://git.kernel.org/stable/c/455217ac9db0cf9349b3933664355e907bb1a569
- https://git.kernel.org/stable/c/9f28205ddb76e86cac418332e952241d85fed0dc
- https://git.kernel.org/stable/c/a2d1cca955ed34873e524cc2e6e885450d262f05
- https://git.kernel.org/stable/c/c32da44cc9298eaa6109e3fc2c2b4e07cc4bf11b
- https://git.kernel.org/stable/c/e8db70537878e1bb3fd83e5abcc6feefc0587828
- https://git.kernel.org/stable/c/ee01b2f2d7d0010787c2343463965bbc283a497f
References
- https://git.kernel.org/stable/c/01a83237644d6822bc7df2c5564fc81b0df84358
- https://git.kernel.org/stable/c/084819b0d8b1bd433b90142371eb9450d657f8ca
- https://git.kernel.org/stable/c/455217ac9db0cf9349b3933664355e907bb1a569
- https://git.kernel.org/stable/c/9f28205ddb76e86cac418332e952241d85fed0dc
- https://git.kernel.org/stable/c/a2d1cca955ed34873e524cc2e6e885450d262f05
- https://git.kernel.org/stable/c/c32da44cc9298eaa6109e3fc2c2b4e07cc4bf11b
- https://git.kernel.org/stable/c/e8db70537878e1bb3fd83e5abcc6feefc0587828
- https://git.kernel.org/stable/c/ee01b2f2d7d0010787c2343463965bbc283a497f
- https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
- https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html