Linux: Improper Synchronization
CVE-2026-53277 is a high-severity improper synchronization vulnerability in Linux, with a CVSS 3.1 base score of 8.8 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 0648b375aa951cc15d9e90f9ac4de71e0b51fa45, 97706097f9b851cfe55c3b00b083dfc2bcf542bc, ec42b4ed1b072ea2d03f086061aa67bad6d8de39 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 0.11% 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 0648b375aa951cc15d9e90f9ac4de71e0b51fa45 or 97706097f9b851cfe55c3b00b083dfc2bcf542bc or ec42b4ed1b072ea2d03f086061aa67bad6d8de39 or f2ca45b50d4216c9cc7ffabf50d9ad1932209251, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.36 or 7.0.13, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | be04cebf3e78874627dc1042991d5d504464a5cc up to, but not including, 0648b375aa951cc15d9e90f9ac4de71e0b51fa45; be04cebf3e78874627dc1042991d5d504464a5cc up to, but not including, 97706097f9b851cfe55c3b00b083dfc2bcf542bc; be04cebf3e78874627dc1042991d5d504464a5cc up to, but not including, ec42b4ed1b072ea2d03f086061aa67bad6d8de39; be04cebf3e78874627dc1042991d5d504464a5cc up to, but not including, f2ca45b50d4216c9cc7ffabf50d9ad1932209251; 6.12 | 0648b375aa951cc15d9e90f9ac4de71e0b51fa45, 97706097f9b851cfe55c3b00b083dfc2bcf542bc, ec42b4ed1b072ea2d03f086061aa67bad6d8de39, f2ca45b50d4216c9cc7ffabf50d9ad1932209251 |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Linux | Linux Kernel | 6.12 up to, but not including, 6.18.36; 6.19 up to, but not including, 7.0.13; 7.1 | 6.18.36, 7.0.13 |
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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:C/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA |
| CVSS 3.1 | 7.0 | High | CNA |
Official description
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Take the SRCU lock for page table walks in fault injection and AT emulation walk_s1() and kvm_walk_nested_s2() expect to be called while holding kvm->srcu to guard against memslot changes. While this is generally the case, __kvm_at_s12() and __kvm_find_s1_desc_level() call into the respective walkers without taking kvm->srcu. Fix by acquiring kvm->srcu prior to the table walk in both instances.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Synchronization
The product utilizes multiple threads, processes, components, or systems to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes.
How developers prevent this class of flaw
- Use industry standard APIs to synchronize your code.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Third-party and government advisories
- access.redhat.com/security/cve/CVE-2026-53277Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2492725Issue Tracking, Third Party Advisory
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53277.jsonThird Party Advisory
Other references
Recent Improper Synchronization vulnerabilities
- 8.2 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.5 High severity
- 9.1 Critical severity
- 7.0 High severity
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