Linux: Use After Free
CVE-2026-31581 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions e719232f4552e29de8027a83918ea94434be87af, e247a0e01d15ed420f77ec5e2335721bf430a5b3, ba88461f7653636c48321ca993006a74724c2f41 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to e719232f4552e29de8027a83918ea94434be87af or e247a0e01d15ed420f77ec5e2335721bf430a5b3 or ba88461f7653636c48321ca993006a74724c2f41 or e88354b381e2006de63d6b052ed7005c9a47d00e, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.136 or 6.12.83 or 6.18.24 or 6.19.14, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f2d06d4e129e2508e356136f99bb20a332ff1a00 up to, but not including, e719232f4552e29de8027a83918ea94434be87af; b889a7d68d7e76b8795b754a75c91a2d561d5e8c up to, but not including, e247a0e01d15ed420f77ec5e2335721bf430a5b3; ea8cc56db659cf0ae57073e32a4735ead7bd7ee3 up to, but not including, ba88461f7653636c48321ca993006a74724c2f41; b754e831a94f82f2593af806741392903f359168 up to, but not including, e88354b381e2006de63d6b052ed7005c9a47d00e; 57860a80f03f9dc69a34a5c37b0941ad032a0a8c up to, but not including, af75b486f7e883e3422ece23c8d727e6815144a0; a0810c3d6dd2d29a9b92604d682eacd2902ce947 up to, but not including, d21e8a2af4869b5890b34e081d5aeadc93e9cd5c; a0810c3d6dd2d29a9b92604d682eacd2902ce947 up to, but not including, 3dc20d1981d6a67d8184498a5da272942dde1e65; a0810c3d6dd2d29a9b92604d682eacd2902ce947 up to, but not including, 51f6532790b74ffdd6970bc848358a2838c1c185; and 13 more ranges | e719232f4552e29de8027a83918ea94434be87af, e247a0e01d15ed420f77ec5e2335721bf430a5b3, ba88461f7653636c48321ca993006a74724c2f41, e88354b381e2006de63d6b052ed7005c9a47d00e, af75b486f7e883e3422ece23c8d727e6815144a0, d21e8a2af4869b5890b34e081d5aeadc93e9cd5c |
| Linux | Linux Kernel | before 6.6.136; 6.12 up to, but not including, 6.12.83; 6.13 up to, but not including, 6.18.24; 6.19 up to, but not including, 6.19.14; 7.0 up to, but not including, 7.0.1 | 6.6.136, 6.12.83, 6.18.24, 6.19.14, 7.0.1 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: ALSA: 6fire: fix use-after-free on disconnect In usb6fire_chip_abort(), the chip struct is allocated as the card's private data (via snd_card_new with sizeof(struct sfire_chip)). When snd_card_free_when_closed() is called and no file handles are open, the card and embedded chip are freed synchronously. The subsequent chip->card = NULL write then hits freed slab memory. Call trace: usb6fire_chip_abort sound/usb/6fire/chip.c:59 [inline] usb6fire_chip_disconnect+0x348/0x358 sound/usb/6fire/chip.c:182 usb_unbind_interface+0x1a8/0x88c drivers/usb/core/driver.c:458 ... hub_event+0x1a04/0x4518 drivers/usb/core/hub.c:5953 Fix by moving the card lifecycle out of usb6fire_chip_abort() and into usb6fire_chip_disconnect(). The card pointer is saved in a local before any teardown, snd_card_disconnect() is called first to prevent new opens, URBs are aborted while chip is still valid, and snd_card_free_when_closed() is called last so chip is never accessed after the card may be freed.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/3dc20d1981d6a67d8184498a5da272942dde1e65
- git.kernel.org/stable/c/51f6532790b74ffdd6970bc848358a2838c1c185
- git.kernel.org/stable/c/af75b486f7e883e3422ece23c8d727e6815144a0
- git.kernel.org/stable/c/b9c826916fdce6419b94eb0cd8810fdac18c2386
- git.kernel.org/stable/c/d21e8a2af4869b5890b34e081d5aeadc93e9cd5c
- git.kernel.org/stable/c/e88354b381e2006de63d6b052ed7005c9a47d00e
Other references
Recent Use After Free vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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