CVE-2024-46840: Linux kernel · btrfs: clean up our handling of refs == 0 in snapshot delete
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.4.0-1135.145~18.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 23:46 UTC
- Patch
- Available – fixed in 5.4.0-1135.145~18.04.1, 5.4.0-1140.147~18.04.1, 5.4.0-1139.148~18.04.1 +75
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 27 Sep 2024
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.
Patches and advisories
- ubuntu.com/security/notices/USN-7088-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7088-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7088-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7088-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7100-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7100-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7088-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7119-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7123-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7144-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7154-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7155-1 (opens in a new tab)
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-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gkeoppkg:deb/ubuntu/linux-gkeop?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.
AI-suggested
A patch is available and has been released in multiple Linux kernel versions including 5.4.0-1135.145~18.04.1 and 5.15.0-1072.78~20.04.1. Users and administrators should update their Linux kernel to one of the fixed versions to remediate this vulnerability. No additional mitigation actions are required beyond applying the official kernel updates.
Description
CVE-2024-46840 is a vulnerability in the Linux kernel's Btrfs filesystem related to improper handling of reference counts (refs) equal to zero during snapshot deletion. The issue involves the kernel using BUG_ON checks that can cause crashes due to transient incorrect answers or extent tree corruption. The vulnerability has been addressed by replacing these BUG_ON checks with proper error handling and returning more appropriate error codes. This flaw affects multiple Linux kernel versions prior to fixed releases in the 5.4 and 5.15 series.
References
- ubuntu.com/security/CVE-2024-46840 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-46840 (opens in a new tab)
- git.kernel.org/linus/b8ccef048354074a548f108e51d0557d6adfd3a3 (opens in a new tab)
- git.kernel.org/stable/c/c847b28a799733b04574060ab9d00f215970627d (opens in a new tab)
- git.kernel.org/stable/c/71291aa7246645ef622621934d2067400380645e (opens in a new tab)
- git.kernel.org/stable/c/c60676b81fab456b672796830f6d8057058f029c (opens in a new tab)
- git.kernel.org/stable/c/728d4d045b628e006b48a448f3326a7194c88d32 (opens in a new tab)
- git.kernel.org/stable/c/9cc887ac24b7a0598f4042ae9af6b9a33072f75b (opens in a new tab)
- git.kernel.org/stable/c/7d1df13bf078ffebfedd361d714ff6cee1ff01b9 (opens in a new tab)
- git.kernel.org/stable/c/03804641ec2d0da4fa088ad21c88e703d151ce16 (opens in a new tab)
- git.kernel.org/stable/c/b8ccef048354074a548f108e51d0557d6adfd3a3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7088-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7088-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7088-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7088-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7100-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7100-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7088-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7119-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7123-1 (opens in a new tab)