CVE-2026-55687: Stack Overflow (CVSS 7.5)

Description

ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. Versions 6.0.1, 5.5.4, 5.4.4, 5.3.5, and possibly prior contain an out-of-bounds write in jpeg_parse_dqt_marker() in components/esp_driver_jpeg/jpeg_parse_marker.c because the attacker-controlled DQT marker Tq nibble is used as an index into the qt_tbl array without validating that it is in the range 0..3, allowing malformed JPEG input to corrupt stack memory and reliably trigger a denial of service. This issue is fixed in version 6.0.2 and is expected to be fixed in versions 5.5.5, 5.4.5, and 5.3.6.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0039

Probability of exploitation

0.31%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-121 CWE-121

CWE-787 Out-of-bounds Write

References

Other References

https://github.com/espressif/esp-idf/commit/303c01305acb8ae5c4eb24a1786300681b4822a4 https://github.com/espressif/esp-idf/commit/6ffafe8e93142ef8ffe51a6311d4abfc0f10fe77 https://github.com/espressif/esp-idf/commit/7ccfc00f39faf1b7e5919f45b56fe44ba699d7c1 https://github.com/espressif/esp-idf/commit/82c5c2dad45313786fb7e973059bc9094d95c3b2 https://github.com/espressif/esp-idf/commit/f2df45bcedef11354e83c31a9718d680a68422c4 https://github.com/espressif/esp-idf/releases/tag/v6.0.2 https://github.com/espressif/esp-idf/security/advisories/GHSA-v6r2-f6p2-88cj

Frequently Asked Questions

What is CVE-2026-55687? +

ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. Versions 6.0.1, 5.5.4, 5.4.4, 5.3.5, and possibly prior contain an out-of-bounds write in jpeg_parse_dqt_marker() in components/esp_driver_jpeg/jpeg_parse_marker.c because the attacker-controlled DQT marker Tq nibble is used as an index into the qt_tbl array without validating that it is in the range 0..3, allowing malformed JPEG input to corrupt stack memory and reliably trigger a denial of service. This issue is fixed in version 6.0.2 and is expected to be fixed in versions 5.5.5, 5.4.5, and 5.3.6. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-55687? +

CVE-2026-55687 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0039, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-55687? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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