# CVE-2026-61497: TinyUSB < 0.21.0 Integer Underflow via HID Report Descriptor Parser

Status: published. Published: 2026-11-03. Updated: 2026-11-09.

TinyUSB before 0.21.0 contains an integer underflow vulnerability in the HID host report descriptor parser tuh_hid_parse_report_descriptor() in src/class/hid/hid_host.c that allows a malicious USB device to trigger an out-of-bounds read by subtracting an item size from the remaining descriptor length without validating the item fits within the remaining buffer. Attackers can present a crafted USB device with a truncated report descriptor causing the uint16_t desc_len value to underflow, resulting in out-of-bounds memory reads and denial of service on the host system.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/hathach/tinyusb/releases/tag/0.21.0
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/hathach/tinyusb/commit/85047e1777f5c20b7a936aa905c746125d3ed066

## Affected products and versions

- hathach / TinyUSB (hathach/tinyusb): ≥ 0; < 0.21.0 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 5.2 (medium); CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 5.2 (medium); CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H; source: CNA: VulnCheck

- CVSS 4.0: 5.2 (medium); CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 5.2 (medium); CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.28% as of 2026-11-09; percentile 20.20%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-191

## Exploit evidence

- exploit: https://gist.github.com/Shukhrat-03/8fe6e5881614a7f86b5d2b87d44ea706 (CNA: VulnCheck)

## References

- https://github.com/hathach/tinyusb/releases/tag/0.21.0 (CNA: VulnCheck; patch, release-notes)

- https://github.com/hathach/tinyusb/commit/85047e1777f5c20b7a936aa905c746125d3ed066 (CNA: VulnCheck; issue-tracking, patch)

- https://www.vulncheck.com/advisories/tinyusb-integer-underflow-via-hid-report-descriptor-parser (CNA: VulnCheck; third-party-advisory)

- https://gist.github.com/Shukhrat-03/8fe6e5881614a7f86b5d2b87d44ea706 (CNA: VulnCheck; technical-description, exploit)

- https://github.com/hathach/tinyusb/commit/85047e1777f5c20b7a936aa905c746125d3ed066 (disclosure@vulncheck.com)

- https://github.com/hathach/tinyusb/releases/tag/0.21.0 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/tinyusb-integer-underflow-via-hid-report-descriptor-parser (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-61497; retrieved 2026-11-09; source updated 2026-11-09

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61497; retrieved 2026-11-04; source updated 2026-11-03

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-61497; retrieved 2026-11-09; source updated Not reported

Revision: 96d599f1e15a7cc5a30bcaad6f753fd69d0eb2906ac11df1162c8edc957b0e65

Canonical: https://y2.dev/cve/CVE-2026-61497

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