CVE-2025-21832: Linux kernel · block: don't revert iter for -EIOCBQUEUED
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 6.8.0-1032.34~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1032.34~22.04.1, 6.8.0-1034.39~22.04.1, 6.8.0-1033.35~22.04.1 +30
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 6 Mar 2025
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 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: block: don't revert iter for -EIOCBQUEUED blkdev_read_iter() has a few odd checks, like gating the position and count adjustment on whether or not the result is bigger-than-or-equal to zero (where bigger than makes more sense), and not checking the return value of blkdev_direct_IO() before doing an iov_iter_revert(). The latter can lead to attempting to revert with a negative value, which when passed to iov_iter_revert() as an unsigned value will lead to throwing a WARN_ON() because unroll is bigger than MAX_RW_COUNT. Be sane and don't revert for -EIOCBQUEUED, like what is done in other spots.
References
- ubuntu.com/security/CVE-2025-21832 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-21832 (opens in a new tab)
- git.kernel.org/linus/b13ee668e8280ca5b07f8ce2846b9957a8a10853 (opens in a new tab)
- git.kernel.org/stable/c/68f16d3034a06661245ecd22f0d586a8b4e7c473 (opens in a new tab)
- git.kernel.org/stable/c/6c26619effb1b4cb7d20b4e666ab8f71f6a53ccb (opens in a new tab)
- git.kernel.org/stable/c/84671b0630ccb46ae9f1f99a45c7d63ffcd6a474 (opens in a new tab)
- git.kernel.org/stable/c/a58f136bad29f9ae721a29d98c042fddbee22f77 (opens in a new tab)
- git.kernel.org/stable/c/b13ee668e8280ca5b07f8ce2846b9957a8a10853 (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7521-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7652-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7653-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7651-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-7737-1 (opens in a new tab)