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Fencer Vulns
high 8.8

CVE-2023-43636 json

Rootfs Not Protected

published 2023-09-20 3 y ago modified 2026-06-17 4 mo ago also GHSA-5h7v-g49c-h887 , GO-2026-4435 , EUVD-2023-48036

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

In EVE OS, the “measured boot” mechanism prevents a compromised device from accessing the encrypted data located in the vault.

As per the “measured boot” design, the PCR values calculated at different stages of the boot process will change if any of their respective parts are changed.

This includes, among other things, the configuration of the bios, grub, the kernel cmdline, initrd, and more.

However, this mechanism does not validate the entire rootfs, so an attacker can edit the filesystem and gain control over the system.

As the default filesystem used by EVE OS is squashfs, this is somewhat harder than an ext4, which is easily changeable.

This will not stop an attacker, as an attacker can repackage the squashfs with their changes in it and replace the partition altogether.

This can also be done directly on the device, as the “003-storage-init” container contains the “mksquashfs” and “unsquashfs” binaries (with the corresponding libs).

An attacker can gain full control over the device without changing the PCR values, thus not triggering the “measured boot” mechanism, and having full access to the vault.

Note:

This issue was partially fixed in these commits (after disclosure to Zededa), where the config partition measurement was added to PCR13:

• aa3501d6c57206ced222c33aea15a9169d629141

• 5fef4d92e75838cc78010edaed5247dfbdae1889.

This issue was made viable in version 9.0.0 when the calculation was moved to PCR14 but it was not included in the measured boot.

Patch / fix

  • go github.com/lf-edge/eve/pkg/grub 0.0.0-20220708121648-5fef4d92e758
  • go github.com/lf-edge/eve 0.0.0-20220708121648-5fef4d92e758
  • LF-Edge, Zededa EVE OS 8.6.0, 9.5.0
  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20260226T182644-150000.1.149.1

suse advisories SUSE-SU-2026:0757-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 y ago

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
GitHub 3.1 6.7 CVSS:3.1/AV:P/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
go github.com/lf-edge/eve/pkg/grub
<0.0.0-20220708121648-5fef4d92e758
0.0.0-20220708121648-5fef4d92e758
go github.com/lf-edge/eve
<0.0.0-20220708121648-5fef4d92e758
0.0.0-20220708121648-5fef4d92e758

Affected products

  • LF-Edge, Zededa EVE OS

Classification

Weakness
  • CWE-345 Insufficient Verification of Data Authenticity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.