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VulnerabilityPublished Updated

CVE-2024-35803: Linux kernel · x86/efistub: Call mixed mode boot services on the firmware's stack

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-35.35 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.8.0-35.35, 6.8.0-1009.9, 6.8.0-1008.8 +7
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 17 May 2024

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-35.35
Fixed in
  • 6.8.0-35.35
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1009.9
Fixed in
  • 6.8.0-1009.9
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1008.8
Fixed in
  • 6.8.0-1008.8
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1008.9
Fixed in
  • 6.8.0-1008.9
Ubuntu 24.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1004.7
Fixed in
  • 6.8.0-1004.7
Ubuntu 24.04 LTSlinux-ibmpkg:deb/ubuntu/linux-ibm?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1006.6
Fixed in
  • 6.8.0-1006.6

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

An official fix is available and should be applied. The fix involves recording and switching to the firmware stack pointer for EFI boot service calls in mixed mode, preventing stack overruns and memory corruption. Users should update to patched Linux kernel versions as provided by their distribution vendors. No additional mitigations are indicated or required beyond applying the official patch.

Description

A vulnerability in the Linux kernel's x86 EFI stub was resolved. The EFI stub normally calls EFI boot services using the firmware's stack, which must be at least 128k in size. In mixed mode boot, a smaller 16k stack was used, causing EFI boot service calls to use an undersized decompressor stack. Recent changes moved the boot stack location, making overruns corrupt critical memory sections. The fix records the firmware stack pointer on entry and switches to it for EFI boot service calls, preventing stack corruption.

References

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