Linux: Use After Free
CVE-2026-23454 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.0 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 b88edf12fc3779521ae5f6f1584153b15f7da6df, e23bf444512cb85d76012080a76cd1f9e967448e, 249e905571583a434d4ea8d6f92ccc0eef337115 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 b88edf12fc3779521ae5f6f1584153b15f7da6df or e23bf444512cb85d76012080a76cd1f9e967448e or 249e905571583a434d4ea8d6f92ccc0eef337115 or 2b001901f689021acd7bf2dceed74a1bdcaaa1f9, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.203 or 6.1.167 or 6.6.130 or 6.12.78, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, b88edf12fc3779521ae5f6f1584153b15f7da6df; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, e23bf444512cb85d76012080a76cd1f9e967448e; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, 249e905571583a434d4ea8d6f92ccc0eef337115; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, 2b001901f689021acd7bf2dceed74a1bdcaaa1f9; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, afdb1533eb9c05432aeb793a7280fa827c502f5c; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, 05d345719d85b927cba74afac4d5322de3aa4256; ca9c54d2d6a5ab2430c4eda364c77125d62e5e0f up to, but not including, fa103fc8f56954a60699a29215cb713448a39e87; 5.13 | b88edf12fc3779521ae5f6f1584153b15f7da6df, e23bf444512cb85d76012080a76cd1f9e967448e, 249e905571583a434d4ea8d6f92ccc0eef337115, 2b001901f689021acd7bf2dceed74a1bdcaaa1f9, afdb1533eb9c05432aeb793a7280fa827c502f5c, 05d345719d85b927cba74afac4d5322de3aa4256 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 5.13 up to, but not including, 5.15.203; 5.16 up to, but not including, 6.1.167; 6.2 up to, but not including, 6.6.130; 6.7 up to, but not including, 6.12.78; 6.13 up to, but not including, 6.18.20; 6.19 up to, but not including, 6.19.10; 7.0 | 5.15.203, 6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.10 |
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
- HighSuccess depends on conditions outside the attacker's control.
- 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:H/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: net: mana: fix use-after-free in mana_hwc_destroy_channel() by reordering teardown A potential race condition exists in mana_hwc_destroy_channel() where hwc->caller_ctx is freed before the HWC's Completion Queue (CQ) and Event Queue (EQ) are destroyed. This allows an in-flight CQ interrupt handler to dereference freed memory, leading to a use-after-free or NULL pointer dereference in mana_hwc_handle_resp(). mana_smc_teardown_hwc() signals the hardware to stop but does not synchronize against IRQ handlers already executing on other CPUs. The IRQ synchronization only happens in mana_hwc_destroy_cq() via mana_gd_destroy_eq() -> mana_gd_deregister_irq(). Since this runs after kfree(hwc->caller_ctx), a concurrent mana_hwc_rx_event_handler() can dereference freed caller_ctx (and rxq->msg_buf) in mana_hwc_handle_resp(). Fix this by reordering teardown to reverse-of-creation order: destroy the TX/RX work queues and CQ/EQ before freeing hwc->caller_ctx. This ensures all in-flight interrupt handlers complete before the memory they access is 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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/05d345719d85b927cba74afac4d5322de3aa4256
- git.kernel.org/stable/c/249e905571583a434d4ea8d6f92ccc0eef337115
- git.kernel.org/stable/c/2b001901f689021acd7bf2dceed74a1bdcaaa1f9
- git.kernel.org/stable/c/afdb1533eb9c05432aeb793a7280fa827c502f5c
- git.kernel.org/stable/c/b88edf12fc3779521ae5f6f1584153b15f7da6df
- git.kernel.org/stable/c/e23bf444512cb85d76012080a76cd1f9e967448e
- git.kernel.org/stable/c/fa103fc8f56954a60699a29215cb713448a39e87
Other references
Recent Use After Free vulnerabilities
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