CVE-2026-25532
ESF-IDF is Vulnerable to WPS Enrollee Fragment Integer Underflow
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.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
6.3
ESF-IDF is Vulnerable to WPS Enrollee Fragment Integer Underflow
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.
- Record
CVE-2026-25532- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H - Weakness
- CWE-191
- Updated
- 2026-11-02
EUVDEUVD-2026-5376
6.3
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.
- Record
EUVD-2026-5376- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H - Updated
- 2026-11-02
NVD
6.3
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.
- Record
CVE-2026-25532- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H - CVSS 3.1
- 8.0 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-191
- Updated
- 2026-11-02
OSV
6.3
ESF-IDF is Vulnerable to WPS Enrollee Fragment Integer Underflow
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.
- Record
CVE-2026-25532- CVSS 3.1
- 6.3 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H - Weakness
- CWE-191
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-25532 is a medium vulnerability (CVSS 6.3) in Espressif Esp-idf, published February 4, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.25%, the 16th percentile. No source names a fixed version.
References
github.com/espressif/esp-idf/security/advisories/GHSA-m2h2-683f-9mw7
github.com/espressif/esp-idf/commit/60f992a26de17bb5406f2149a2f8282dd7ad1c59
github.com/espressif/esp-idf/commit/6f6766f917bc940ffbcc97eac4765a6ab15d5f79
github.com/espressif/esp-idf/commit/73a587d42a57ece1962b6a4c530b574600650f63
github.com/espressif/esp-idf/commit/b209fae993d795255827ce6b2b0d6942a377f5d4
github.com/espressif/esp-idf/commit/b88befde6b5addcdd8d7373ce55c8052dea1e855