CVE-2026-23356: Linux kernel · drbd: fix "LOGIC BUG" in drbd_al_begin_io_nonblock()
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 3% 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 is available and should be applied to affected Linux kernel versions to fix the logic bug in the DRBD subsystem. The vendor advisory confirms that this issue is fixed in updated kernel releases. Users should update their Linux kernel to a patched version to prevent potential kernel crashes and resync inconsistencies. No additional mitigation is required beyond applying the official fix.
Description
A logic bug in the Linux kernel's DRBD subsystem was fixed in function drbd_al_begin_io_nonblock(). The bug involved incorrect assumptions about locking and reference counting during activity log operations, potentially causing resync and application IO to not be mutually exclusive during active resyncs. This could lead to kernel crashes or inconsistent resync states. The fix improves error handling and prevents kernel crashes by properly managing activity log references and returning error codes when necessary.
References
- ubuntu.com/security/CVE-2026-23356 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23356 (opens in a new tab)
- git.kernel.org/linus/ab140365fb62c0bdab22b2f516aff563b2559e3b (opens in a new tab)
- git.kernel.org/stable/c/7752569fc78e89794ce28946529850282233f99d (opens in a new tab)
- git.kernel.org/stable/c/ab140365fb62c0bdab22b2f516aff563b2559e3b (opens in a new tab)
- git.kernel.org/stable/c/d1ef3aed4df2ef1fe46befd8f2da9a6ec5445508 (opens in a new tab)
- git.kernel.org/stable/c/e91d8d6565b7819d13dab21d4dbed5b45efba59b (opens in a new tab)
- git.kernel.org/stable/c/eef1390125b660b8b61f9f227a03bb9c5e6d36a5 (opens in a new tab)
- git.kernel.org/stable/c/f558e5404a72054b525dced1a0c66aa95a144153 (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)