Out-of-bounds stack read and write in Zephyr WNC-M14A2A modem socket-notify parsing

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-12519
StatePUBLISHED
Assignerzephyr
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-17 17:16:38 UTC
Updated2026-08-17 19:16:24 UTC
DescriptionThe WNC-M14A2A LTE-M modem driver mishandles unsolicited %NOTIFYEV: events in on_cmd_socknotifyev() (drivers/modem/vendor_standalone/wncm14a2a.c). The response line is linearized into a fixed 40-byte stack buffer via net_buf_linearize(), which caps the copy at 39 bytes and returns out_len <= 39. The two quote-delimiter scanning loops, however, were bounded by len — the full CR/LF-delimited frame length returned by net_buf_findcrlf() — rather than by out_len. When a %NOTIFYEV: line longer than 39 bytes contains no " within the linearized region, the loop indices p1/p2 walk past value[39] and read adjacent stack memory until a stray quote byte is found or the index reaches len. The over-read string is then passed to strncmp()/atoi()/LOG_*, and if a quote byte is found out of bounds the subsequent value[p2] = '\0' performs a single-NUL out-of-bounds stack write at an attacker-influenced offset. The %NOTIFYEV: payload carries network-derived content (LTIME network time, SIB1 base-station system information, CSPS/RRCSTATE), so a rogue cellular base station, a malicious or compromised modem module, or RF manipulation that induces an over-long notify line reaches the defect without any application interaction; the handler runs automatically on the unsolicited event in the modem RX thread. The impact is out-of-bounds stack disclosure (into logs and parsing) and stack corruption that can crash the modem RX thread (denial of service). The write offset is only weakly controlled, so memory-safe code execution is not demonstrated. The fix bounds both scanning loops by out_len, keeping all accesses within the linearized buffer.

Risk And Classification

Primary CVSS: v3.1 5 MEDIUM from [email protected]

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

EPSS: 0.001630000 probability, percentile 0.059830000 (date 2026-08-18)

Problem Types: CWE-787 | CWE-787 memory-safety

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5MEDIUMCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
3.1CNACVSS5MEDIUMCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

CVSS v3.1 Breakdown

Attack Vector
Adjacent
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Zephyrproject Zephyr affected 1.13.0 4.4.2 semver Not specified

References

ReferenceSourceLinkTags
github.com/zephyrproject-rtos/zephyr/commit/c516cb7c14f8b0537811764daa94... [email protected] github.com
github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-8hrc-q8cp-... [email protected] github.com
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