CVE-2024-26999: Linux kernel · serial/pmac_zilog: Remove flawed mitigation for rx irq flood
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.4.0-1128.138~18.04.1 : update Linux kernel when convenient.
Data as of 28 Oct 2026, 10:59 UTC
- Patch
- Available – fixed in 5.4.0-1128.138~18.04.1, 5.4.0-1133.140~18.04.1, 5.4.0-1132.141~18.04.1 +68
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 1 May 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-6893-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6893-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-6893-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-4 (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-ibmpkg:deb/ubuntu/linux-ibm?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: serial/pmac_zilog: Remove flawed mitigation for rx irq flood The mitigation was intended to stop the irq completely. That may be better than a hard lock-up but it turns out that you get a crash anyway if you're using pmac_zilog as a serial console: ttyPZ0: pmz: rx irq flood ! BUG: spinlock recursion on CPU#0, swapper/0 That's because the pr_err() call in pmz_receive_chars() results in pmz_console_write() attempting to lock a spinlock already locked in pmz_interrupt(). With CONFIG_DEBUG_SPINLOCK=y, this produces a fatal BUG splat. The spinlock in question is the one in struct uart_port. Even when it's not fatal, the serial port rx function ceases to work. Also, the iteration limit doesn't play nicely with QEMU, as can be seen in the bug report linked below. A web search for other reports of the error message "pmz: rx irq flood" didn't produce anything. So I don't think this code is needed any more. Remove it.
References
- ubuntu.com/security/CVE-2024-26999 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-26999 (opens in a new tab)
- git.kernel.org/linus/1be3226445362bfbf461c92a5bcdb1723f2e4907 (opens in a new tab)
- git.kernel.org/stable/c/7a3bbe41efa55323b6ea3c35fa15941d4dbecdef (opens in a new tab)
- git.kernel.org/stable/c/bbaafbb4651fede8d3c3881601ecaa4f834f9d3f (opens in a new tab)
- git.kernel.org/stable/c/52aaf1ff14622a04148dbb9ccce6d9de5d534ea7 (opens in a new tab)
- git.kernel.org/stable/c/ca09dfc3cfdf89e6af3ac24e1c6c0be5c575a729 (opens in a new tab)
- git.kernel.org/stable/c/1be3226445362bfbf461c92a5bcdb1723f2e4907 (opens in a new tab)
- ubuntu.com/security/notices/USN-6893-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6893-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-6893-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-4 (opens in a new tab)