CVE-2026-23303: Linux kernel · smb: client: Don't log plaintext credentials in cifs_set_cifscreds
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1112.119~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1112.119~20.04.1, 5.15.0-1117.126~20.04.1, 5.15.0-1117.126~20.04.2 +63
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch addressing this vulnerability is available and should be applied. The Ubuntu security advisory USN-8567-1 provides updated Linux kernel packages that remove the debug logging of plaintext credentials. Users should update to the fixed kernel versions to mitigate this issue. If updating is not immediately possible, disabling debug logging for the SMB client can prevent exposure of plaintext credentials. No other specific mitigations are indicated by the vendor advisory.
Description
A vulnerability in the Linux kernel's SMB client was resolved where debug logging in the cifs_set_cifscreds() function exposed plaintext usernames and passwords. This occurred when debug logging was enabled, causing sensitive credential information to be logged. The issue has been fixed by removing the debug log that exposed these credentials. The vulnerability affects specific Linux kernel versions and has a medium severity rating with a CVSS score of 5.5. A patch is available as detailed in the Ubuntu security advisory USN-8567-1.
References
- ubuntu.com/security/CVE-2026-23303 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23303 (opens in a new tab)
- git.kernel.org/linus/2f37dc436d4e61ff7ae0b0353cf91b8c10396e4d (opens in a new tab)
- git.kernel.org/stable/c/2ef0fc3bf49db2b9df36d5f44508c9e384bfa2a1 (opens in a new tab)
- git.kernel.org/stable/c/2f37dc436d4e61ff7ae0b0353cf91b8c10396e4d (opens in a new tab)
- git.kernel.org/stable/c/3990f352bb0adc8688d0949a9c13e3110570eb61 (opens in a new tab)
- git.kernel.org/stable/c/3e182701db612ddd794ccd5ed822e6cc1db2b972 (opens in a new tab)
- git.kernel.org/stable/c/b746a357abfb8fdb0a171d51ec5091e786d34be1 (opens in a new tab)
- git.kernel.org/stable/c/ff0ece8ed04180c52167c003362284b23cf54e8d (opens in a new tab)
- ubuntu.com/security/notices/USN-8567-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8596-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8575-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8576-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8597-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-2 (opens in a new tab)