Linux: Out-of-bounds Read
CVE-2025-38556 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 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 6cdf6c708717c5c6897d0800a1793e83757c7491, eeeaba737919bdce9885e2a00ac2912f61a3684d, 3c86548a20d7bc2861aa4de044991a327bebad1a 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 0.18% 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 6cdf6c708717c5c6897d0800a1793e83757c7491 or eeeaba737919bdce9885e2a00ac2912f61a3684d or 3c86548a20d7bc2861aa4de044991a327bebad1a or 810189546cb6c8f36443ed091d91f1f5d2fc2ec7, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.46 or 6.15.10 or 6.16.1, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | dde5845a529ff753364a6d1aea61180946270bfa up to, but not including, 6cdf6c708717c5c6897d0800a1793e83757c7491; dde5845a529ff753364a6d1aea61180946270bfa up to, but not including, eeeaba737919bdce9885e2a00ac2912f61a3684d; dde5845a529ff753364a6d1aea61180946270bfa up to, but not including, 3c86548a20d7bc2861aa4de044991a327bebad1a; dde5845a529ff753364a6d1aea61180946270bfa up to, but not including, 810189546cb6c8f36443ed091d91f1f5d2fc2ec7; dde5845a529ff753364a6d1aea61180946270bfa up to, but not including, d3b504146c111548ab60b6ef7aad00bfb1db05a2; dde5845a529ff753364a6d1aea61180946270bfa up to, but not including, 8b4a94b1510f6a46ec48494b52ee8f67eb4fc836; dde5845a529ff753364a6d1aea61180946270bfa up to, but not including, 865ad8469fa24de1559f247d9426ab01e5ce3a56; dde5845a529ff753364a6d1aea61180946270bfa up to, but not including, a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd; and 1 more ranges | 6cdf6c708717c5c6897d0800a1793e83757c7491, eeeaba737919bdce9885e2a00ac2912f61a3684d, 3c86548a20d7bc2861aa4de044991a327bebad1a, 810189546cb6c8f36443ed091d91f1f5d2fc2ec7, d3b504146c111548ab60b6ef7aad00bfb1db05a2, 8b4a94b1510f6a46ec48494b52ee8f67eb4fc836 |
| Linux | Linux Kernel | 2.6.20 up to, but not including, 6.12.46; 6.13 up to, but not including, 6.15.10; 6.16 up to, but not including, 6.16.1 | 6.12.46, 6.15.10, 6.16.1 |
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
- NoneNothing can be modified.
- 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:N/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: HID: core: Harden s32ton() against conversion to 0 bits Testing by the syzbot fuzzer showed that the HID core gets a shift-out-of-bounds exception when it tries to convert a 32-bit quantity to a 0-bit quantity. Ideally this should never occur, but there are buggy devices and some might have a report field with size set to zero; we shouldn't reject the report or the device just because of that. Instead, harden the s32ton() routine so that it returns a reasonable result instead of crashing when it is called with the number of bits set to 0 -- the same as what snto32() does.
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
Other references
Recent Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 7.1 High severity
- 7.8 High severity
- 7.8 High severity
- 7.1 High severity
- 7.1 High severity
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