What is CVE-2022-39343?

CVE-2022-39343 is a medium-severity vulnerability in Azure-Rtos Filex, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.6/10. Published 2022-11-08.

How severe is CVE-2022-39343?

Medium severity. CVSS v3 base score is 5.6 out of 10.

Is CVE-2022-39343 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Azure-Rtos Filex

CVE-2022-39343

Azure RTOS FileX is a FAT-compatible file system that’s fully integrated with Azure RTOS ThreadX. In versions before 6.2.0, the Fault Tolerant feature of Azure RTOS FileX includes integer under and overflows which may be exploited to achieve buffer overflow and modify memory contents. When a valid log file with correct ID and checksum is detected by the `_fx_fault_tolerant_enable` function an attempt to recover the previous failed write operation is taken by call of `_fx_fault_tolerant_apply_logs`. This function iterates through the log entries and performs required recovery operations. When properly crafted a log including entries of type `FX_FAULT_TOLERANT_DIR_LOG_TYPE` may be utilized to introduce unexpected behavior. This issue has been patched in version 6.2.0. A workaround to fix line 218 in fx_fault_tolerant_apply_logs.c is documented in the GHSA.

Vulnerability class: Buffer Overflow

Published 2022-11-08 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.6 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.009 (57.8th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 57.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.009 · change: +0.000

Affected products

Azure-Rtos Filex — versions < 6.2.0
Microsoft Azure Rtos Filex

Weakness classification (CWE)

Public proof-of-concept exploits

szymonh/szymonh

References

github.com/azure-rtos/filex/security/advisories/GHSA-8jqf-wjhq-4w9f (Exploit, Third Party Advisory, Mitigation)
github.com/azure-rtos/filex/blob/master/common/src/fx_fault_tolerant_apply_logs… (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2022-39343?: CVE-2022-39343 is a medium-severity vulnerability in Azure-Rtos Filex, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.6/10. Published 2022-11-08.
How severe is CVE-2022-39343?: Medium severity. CVSS v3 base score is 5.6 out of 10.
Is CVE-2022-39343 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.