Linux: Use After Free
CVE-2026-53055 is a critical-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions b375c3c7209cc59e40e97998aa9bc768369cca0e, ad73563f3a1edbfddf2724136c6a15826b354e18, 67b53a660e6bf0da2fa8d8872e897a14d8059eaf 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 0.43% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Linux to b375c3c7209cc59e40e97998aa9bc768369cca0e or ad73563f3a1edbfddf2724136c6a15826b354e18 or 67b53a660e6bf0da2fa8d8872e897a14d8059eaf, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.33 or 7.0.10, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f0ae287c50455f7be0d8dd45a803d403c7aa4d2e up to, but not including, b375c3c7209cc59e40e97998aa9bc768369cca0e; f0ae287c50455f7be0d8dd45a803d403c7aa4d2e up to, but not including, ad73563f3a1edbfddf2724136c6a15826b354e18; f0ae287c50455f7be0d8dd45a803d403c7aa4d2e up to, but not including, 67b53a660e6bf0da2fa8d8872e897a14d8059eaf; 6.17 | b375c3c7209cc59e40e97998aa9bc768369cca0e, ad73563f3a1edbfddf2724136c6a15826b354e18, 67b53a660e6bf0da2fa8d8872e897a14d8059eaf |
| Linux | Linux Kernel | 6.17 up to, but not including, 6.18.33; 6.19 up to, but not including, 7.0.10 | 6.18.33, 7.0.10 |
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
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- 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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: crypto: hisilicon/sec2 - prevent req used-after-free for sec During packet transmission, if the system is under heavy load, the hardware might complete processing the packet and free the request memory (req) before the transmission function finishes. If the software subsequently accesses this req, a use-after-free error will occur. The qp_ctx memory exists throughout the packet sending process, so replace the req with the qp_ctx.
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
Recent Use After Free vulnerabilities
- 7.5 High severity
- 8.8 High severity
- 7.8 High severity
- 8.8 High severity
- 8.8 High severity
- 9.6 Critical severity
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