Linux: Out-of-bounds Read
CVE-2026-43350 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 23b54d6cc3ef30a51d984dc74364f24039ae2ecb, 1592a6cd6f653f2d24572a6976c7a775b19f4940, 8bd4cad3f458d11650d51c2d24b03fb1770ae6cc 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 0.32% 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 23b54d6cc3ef30a51d984dc74364f24039ae2ecb or 1592a6cd6f653f2d24572a6976c7a775b19f4940 or 8bd4cad3f458d11650d51c2d24b03fb1770ae6cc or b53b8e98c23310294fc45fc686db5ee860311896, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.136 or 6.12.84 or 6.18.25 or 7.0.2, 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.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | e2f8fbfb8d09c06decde162090fac3ee220aa280 up to, but not including, 23b54d6cc3ef30a51d984dc74364f24039ae2ecb; e2f8fbfb8d09c06decde162090fac3ee220aa280 up to, but not including, 1592a6cd6f653f2d24572a6976c7a775b19f4940; e2f8fbfb8d09c06decde162090fac3ee220aa280 up to, but not including, 8bd4cad3f458d11650d51c2d24b03fb1770ae6cc; e2f8fbfb8d09c06decde162090fac3ee220aa280 up to, but not including, b53b8e98c23310294fc45fc686db5ee860311896; e2f8fbfb8d09c06decde162090fac3ee220aa280 up to, but not including, c8eef12af1cc73031639ea7cf16e0b10e2536b0b; e2f8fbfb8d09c06decde162090fac3ee220aa280 up to, but not including, 38a69f08ee82c450d3e4168707fff2e317dc3ff7; e2f8fbfb8d09c06decde162090fac3ee220aa280 up to, but not including, f8488c07bea2431ee12a6067d736578064fa46b4; e2f8fbfb8d09c06decde162090fac3ee220aa280 up to, but not including, 2757ad3e4b6f9e0fed4c7739594e702abc5cab21; and 1 more ranges | 23b54d6cc3ef30a51d984dc74364f24039ae2ecb, 1592a6cd6f653f2d24572a6976c7a775b19f4940, 8bd4cad3f458d11650d51c2d24b03fb1770ae6cc, b53b8e98c23310294fc45fc686db5ee860311896, c8eef12af1cc73031639ea7cf16e0b10e2536b0b, 38a69f08ee82c450d3e4168707fff2e317dc3ff7 |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Linux | Linux Kernel | 5.4 up to, but not including, 6.6.136; 6.7 up to, but not including, 6.12.84; 6.13 up to, but not including, 6.18.25; 6.19 up to, but not including, 7.0.2 | 6.6.136, 6.12.84, 6.18.25, 7.0.2 |
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
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: smb: client: require a full NFS mode SID before reading mode bits parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS mode SID and reads sid.sub_auth[2] to recover the mode bits. That assumes the ACE carries three subauthorities, but compare_sids() only compares min(a, b) subauthorities. A malicious server can return an ACE with num_subauth = 2 and sub_auth[] = {88, 3}, which still matches sid_unix_NFS_mode and then drives the sub_auth[2] read four bytes past the end of the ACE. Require num_subauth >= 3 before treating the ACE as an NFS mode SID. This keeps the fix local to the special-SID mode path without changing compare_sids() semantics for the rest of cifsacl.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
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/2757ad3e4b6f9e0fed4c7739594e702abc5cab21
- git.kernel.org/stable/c/38a69f08ee82c450d3e4168707fff2e317dc3ff7
- git.kernel.org/stable/c/b53b8e98c23310294fc45fc686db5ee860311896
- git.kernel.org/stable/c/c8eef12af1cc73031639ea7cf16e0b10e2536b0b
- git.kernel.org/stable/c/f8488c07bea2431ee12a6067d736578064fa46b4
Other references
Recent Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 8.2 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 9.1 Critical severity
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