Linux: Out-of-bounds Read
CVE-2025-38736 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 fcb4ce9f729c1d08e53abf9d449340e24c3edee6, 8f141f2a4f2ef8ca865d5921574c3d6535e00a49, 748da80831221ae24b4bc8d7ffb22acd5712a341 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 fcb4ce9f729c1d08e53abf9d449340e24c3edee6 or 8f141f2a4f2ef8ca865d5921574c3d6535e00a49 or 748da80831221ae24b4bc8d7ffb22acd5712a341 or 22042ffedd8c2c6db08ccdd6d4273068eddd3c5c, whichever matches your release line, or a later version.
- Update SIMATIC CN 4100 to V5.0 or a later version.
- Update Linux Kernel to 6.16 or 6.16.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 75947d3200de98a9ded9ad8972e02f1a177097fe up to, but not including, fcb4ce9f729c1d08e53abf9d449340e24c3edee6; 59ed6fbdb1bc03316e09493ffde7066f031c7524 up to, but not including, 8f141f2a4f2ef8ca865d5921574c3d6535e00a49; ccef5ee4adf56472aa26bdd1f821a6d0cd06089a up to, but not including, 748da80831221ae24b4bc8d7ffb22acd5712a341; ee2cd40b0bb46056949a2319084a729d95389386 up to, but not including, 22042ffedd8c2c6db08ccdd6d4273068eddd3c5c; ad1f8313aeec0115f9978bd2d002ef4a8d96c773 up to, but not including, 523eab02fce458fa6d3c51de5bb055800986953e; 4faff70959d51078f9ee8372f8cff0d7045e4114 up to, but not including, 24ef2f53c07f273bad99173e27ee88d44d135b1c; a754ab53993b1585132e871c5d811167ad3c52ff; 6.15.11 up to, but not including, 6.16; and 2 more ranges | fcb4ce9f729c1d08e53abf9d449340e24c3edee6, 8f141f2a4f2ef8ca865d5921574c3d6535e00a49, 748da80831221ae24b4bc8d7ffb22acd5712a341, 22042ffedd8c2c6db08ccdd6d4273068eddd3c5c, 523eab02fce458fa6d3c51de5bb055800986953e, 24ef2f53c07f273bad99173e27ee88d44d135b1c |
| Siemens | SIMATIC CN 4100 | before V5.0 | V5.0 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 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; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 6.15.11 up to, but not including, 6.16; 6.16.2 up to, but not including, 6.16.4; 6.12.43; 6.17 | 6.16, 6.16.4 |
| Debian | Debian Linux | 11.0 | Not stated |
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: net: usb: asix_devices: Fix PHY address mask in MDIO bus initialization Syzbot reported shift-out-of-bounds exception on MDIO bus initialization. The PHY address should be masked to 5 bits (0-31). Without this mask, invalid PHY addresses could be used, potentially causing issues with MDIO bus operations. Fix this by masking the PHY address with 0x1f (31 decimal) to ensure it stays within the valid range.
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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/22042ffedd8c2c6db08ccdd6d4273068eddd3c5c
- git.kernel.org/stable/c/24ef2f53c07f273bad99173e27ee88d44d135b1c
- git.kernel.org/stable/c/523eab02fce458fa6d3c51de5bb055800986953e
- git.kernel.org/stable/c/748da80831221ae24b4bc8d7ffb22acd5712a341
- git.kernel.org/stable/c/8f141f2a4f2ef8ca865d5921574c3d6535e00a49
- git.kernel.org/stable/c/fcb4ce9f729c1d08e53abf9d449340e24c3edee6
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlThird Party Advisory
Other references
Recent Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 8.1 High severity
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