Integer overflow in Espressif Esp-Idf
CVE-2026-25532
ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In versions 5.5.2, 5.4.3, 5.3.4, 5.2.6, and 5.1.6, a vulnerability exists in the WPS (Wi-Fi Protected Setup) Enrollee implementation where malformed EAP-WSC packets with truncated payloads can cause integer underflow during fragment length calculation. When processing EAP-Expanded (WSC) messages, the code computes frag_len by subtracting header sizes from the total packet length. If an attacker sends a packet where the EAP Length field covers only the header and flags but omits the expected payload (such as the 2-byte Message Length field when WPS_MSG_FLAG_LEN is set), frag_len becomes negative. This negative value is then implicitly cast to size_t when passed to wpabuf_put_data(), resulting in a very large unsigned value. This issue has been patched in versions 5.5.3, 5.4.4, 5.3.5, 5.2.7, and 5.1.7.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H.
EPSS exploit prediction
EPSS: 0.004 (26.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 26.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.001
Affected products
- Espressif Esp-Idf — versions = 5.4.3, 5.4.3, 5.2.6
Weakness classification (CWE)
References
- github.com/espressif/esp-idf/security/advisories/GHSA-m2h2-683f-9mw7 (Patch, Third Party Advisory)
- github.com/espressif/esp-idf/commit/60f992a26de17bb5406f2149a2f8282dd7ad1c59 (Patch)
- github.com/espressif/esp-idf/commit/6f6766f917bc940ffbcc97eac4765a6ab15d5f79 (Patch)
- github.com/espressif/esp-idf/commit/73a587d42a57ece1962b6a4c530b574600650f63 (Patch)
- github.com/espressif/esp-idf/commit/b209fae993d795255827ce6b2b0d6942a377f5d4 (Patch)
- github.com/espressif/esp-idf/commit/b88befde6b5addcdd8d7373ce55c8052dea1e855 (Patch)
- github.com/espressif/esp-idf/commit/cad36beb4cde27abcf316cd90d8d8dddbc6f213a (Patch)
- github.com/espressif/esp-idf/commit/de28801e8ea6a736b6f0db6fc0c682739363bb41 (Patch)
Frequently asked questions
- What is CVE-2026-25532?
- CVE-2026-25532 is a medium-severity vulnerability in Espressif Esp-Idf, classified under Integer Underflow. CVSS score: 6.3/10. Published 2026-02-04.
- How severe is CVE-2026-25532?
- Medium severity. CVSS v3 base score is 6.3 out of 10.